| PF00064 | Neur | Neuraminidase | Q8AZ87 |
| PF00066 | Notch | LNR domain | Q3T906 |
| PF00146 | NADHdh | NADH dehydrogenase | A0QU29 |
| PF00175 | NAD_binding_1 | Oxidoreductase NAD-binding domain | A0A085ST13 |
| PF00243 | NGF | Nerve growth factor family | P01138 |
| PF00287 | Na_K-ATPase | Sodium / potassium ATPase beta chain | P05026 |
| PF00293 | NUDIX | NUDIX domain | A0A1B2CW14 |
| PF00334 | NDK | Nucleoside diphosphate kinase | Q9Y5B8 |
| PF00374 | NiFeSe_Hases | Nickel-dependent hydrogenase | A0QUM7 |
| PF00483 | NTP_transferase | Nucleotidyl transferase | O22287 |
| PF00877 | NLPC_P60 | NlpC/P60 family | Q8NQA0 |
| PF00880 | Nebulin | Nebulin repeat | |
| PF00881 | Nitroreductase | Nitroreductase family | A6T5Y2 |
| PF00931 | NB-ARC | NB-ARC domain | A1X877 |
| PF00939 | Na_sulph_symp | Sodium:sulfate symporter transmembrane region | Q9KNE0 |
| PF00956 | NAP | Nucleosome assembly protein (NAP) | A0A1D8PT39 |
| PF00960 | Neocarzinostat | Neocarzinostatin family | P0A3S0 |
| PF00999 | Na_H_Exchanger | Sodium/hydrogen exchanger, transmembrane | P48764 |
| PF01029 | NusB | NusB family | P0A780 |
| PF01077 | NIR_SIR | Nitrite and sulphite reductase 4Fe-4S domain | P17846 |
| PF01106 | NifU | NifU-like domain | Q93W20 |
| PF01210 | NAD_Gly3P_dh_N | NAD-dependent glycerol-3-phosphate dehydrogenase N-terminus | P21695 |
| PF01233 | NMT | Myristoyl-CoA:protein N-myristoyltransferase, N-terminal domain | B8N9M6 |
| PF01234 | NNMT_PNMT_TEMT | NNMT/PNMT/TEMT family | P40261 |
| PF01235 | Na_Ala_symp | Sodium:alanine symporter family | Q6LX42 |
| PF01292 | Ni_hydr_CYTB | Prokaryotic cytochrome b561 | P0AAM2 |
| PF01436 | NHL | NHL repeat | Q2Q1W2 |
| PF01513 | NAD_kinase | ATP-NAD kinase N-terminal domain | Q8Y8D7 |
| PF01555 | N6_N4_Mtase | DNA methylase | A0A2N8U1P8 |
| PF01566 | Nramp | Natural resistance-associated macrophage protein-like | C8WJ67 |
| PF01592 | NifU_N | NifU-like N terminal domain | Q9H1K1 |
| PF01699 | Na_Ca_ex | Sodium/calcium exchanger protein | Q57556 |
| PF01733 | Nucleoside_tran | Nucleoside transporter | Q99808 |
| PF01759 | NTR | UNC-6/NTR/C345C module | P01031 |
| PF01773 | Nucleos_tra2_N | Na+ dependent nucleoside transporter N-terminus | Q9HAS3 |
| PF01798 | Nop | snoRNA binding domain, fibrillarin | A0A0E3MJI1 |
| PF01849 | NAC | NAC domain | G1TKK2 |
| PF01909 | NTP_transf_2 | Nucleotidyltransferase domain | Q10295 |
| PF01931 | NTPase_I-T | Protein of unknown function DUF84 | Q9KU27 |
| PF01936 | NYN | NYN domain | Q9Y4F3 |
| PF01939 | NucS_C | Endonuclease NucS C-terminal domain | Q5JER9 |
| PF01957 | NfeD | NfeD-like C-terminal, partner-binding domain | O59179 |
| PF01969 | Ni_insertion | Nickel insertion protein | Q8TYK3 |
| PF01995 | NRD1_2 | NrpR regulatory domains NRD1 and 2 | Q57623 |
| PF02070 | NMU | Neuromedin U | P48645 |
| PF02071 | NSF | Aromatic-di-Alanine (AdAR) repeat | |
| PF02087 | Nitrophorin | Nitrophorin | Q6PQK2 |
| PF02136 | NTF2 | Nuclear transport factor 2 (NTF2) domain | P00947 |
| PF02158 | Neuregulin | Neuregulin intracellular region | |
| PF02211 | NHase_beta_C | Nitrile hydratase beta subunit, C-terminal | Q84FS6 |
| PF02357 | NusG | Transcription termination factor nusG | Q06795 |
| PF02365 | NAM | No apical meristem (NAM) protein | Q9C932 |
| PF02384 | N6_Mtase | N-6 DNA Methylase | A0A031WG99 |
| PF02445 | NadA | Quinolinate synthetase A protein | Q9X1X7 |
| PF02451 | Nodulin | Nodulin | |
| PF02474 | NodA | Nodulation protein A (NodA) | |
| PF02477 | Nairo_nucleo | Nucleocapsid N protein | Q70UR4 |
| PF02540 | NAD_synthase | NAD synthase | Q8IJR9 |
| PF02579 | Nitro_FeMo-Co | Dinitrogenase iron-molybdenum cofactor | O58552 |
| PF02613 | Nitrate_red_del | Nitrate reductase delta subunit | P69853 |
| PF02665 | Nitrate_red_gam | Nitrate reductase gamma subunit | P11350 |
| PF02690 | Na_Pi_cotrans | Na+/Pi-cotransporter | |
| PF02799 | NMT_C | Myristoyl-CoA:protein N-myristoyltransferase, C-terminal domain | B8N9M6 |
| PF02898 | NO_synthase | Nitric oxide synthase, oxygenase domain | P29473 |
| PF02931 | Neur_chan_LBD | Neurotransmitter-gated ion-channel ligand binding domain | P18507 |
| PF02932 | Neur_chan_memb | Neurotransmitter-gated ion-channel transmembrane region | P36544 |
| PF02979 | NHase_alpha | Nitrile hydratase, alpha chain | Q84FS5 |
| PF03000 | NPH3 | NPH3 family | |
| PF03031 | NIF | NLI interacting factor-like phosphatase | Q9GZU7 |
| PF03059 | NAS | Nicotianamine synthase protein | O26771 |
| PF03060 | NMO | Nitronate monooxygenase | A0A031WIF2 |
| PF03066 | Nucleoplasmin | Nucleoplasmin/nucleophosmin domain | P06748 |
| PF03080 | Neprosin | Neprosin | A0A1L7NZU4 |
| PF03096 | Ndr | Ndr family | Q92597 |
| PF03102 | NeuB | NeuB family | A0A6C7NV50 |
| PF03116 | NQR2_RnfD_RnfE | NQR2, RnfD, RnfE family | A0A085SSI3 |
| PF03146 | NtA | Agrin NtA domain | P31696 |
| PF03177 | Nucleoporin_C | Non-repetitive/WGA-negative nucleoporin C-terminal | P38181 |
| PF03206 | NifW | Nitrogen fixation protein NifW | |
| PF03266 | NTPase_1 | NTPase | Q9BSD7 |
| PF03407 | Nucleotid_trans | Nucleotide-diphospho-sugar transferase | |
| PF03446 | NAD_binding_2 | NAD binding domain of 6-phosphogluconate dehydrogenase | A0A0L8BGL4 |
| PF03447 | NAD_binding_3 | Homoserine dehydrogenase, NAD binding domain | A0A2H1A6V9 |
| PF03460 | NIR_SIR_ferr | Nitrite/Sulfite reductase ferredoxin-like half domain | P17846 |
| PF03553 | Na_H_antiporter | Na+/H+ antiporter family | |
| PF03666 | NPR3 | Nitrogen Permease regulator of amino acid transport activity 3 | Q12980 |
| PF03715 | Noc2 | Noc2p family | Q9P7G0 |
| PF03800 | Nuf2 | Nuf2 family | P33895 |
| PF03801 | Ndc80_HEC | HEC/Ndc80p family | P40460 |
| PF03813 | Nrap | Nrap protein domain 1 | P53254 |
| PF03822 | NAF | NAF domain | Q9LDI3 |
| PF03823 | Neurokinin_B | Neurokinin B | |
| PF03824 | NicO | High-affinity nickel-transport protein | |
| PF03825 | Nuc_H_symport | Nucleoside H+ symporter | P0AFF4 |
| PF03892 | NapB | Nitrate reductase cytochrome c-type subunit (NapB) | P39186 |
| PF03916 | NrfD | Polysulphide reductase, NrfD | A7NJ89 |
| PF03927 | NapD | NapD protein | P0A9I5 |
| PF03980 | Nnf1 | Nnf1 | Q09858 |
| PF04054 | Not1 | CCR4-Not complex component, Not1 | A5YKK6 |
| PF04065 | Not3 | Not1 N-terminal domain, CCR4-Not complex component | Q12514 |
| PF04095 | NAPRTase | Nicotinate phosphoribosyltransferase (NAPRTase) family | P43490 |
| PF04096 | Nucleoporin2 | Nup98-96 autopeptidase S59 | P52948 |
| PF04097 | Nic96 | Nup93/Nic96 | P34077 |
| PF04121 | Nup84_Nup100 | Nuclear pore protein 84 / 107 | A2RV69 |
| PF04131 | NanE | Putative N-acetylmannosamine-6-phosphate epimerase | X5EM89 |
| PF04135 | Nop10p | Nucleolar RNA-binding protein, Nop10p family | Q9NPE3 |
| PF04142 | Nuc_sug_transp | Nucleotide-sugar transporter | Q61420 |
| PF04147 | Nop14 | Nop14-like family | Q99207 |
| PF04153 | NOT2_3_5_C | NOT2/NOT3/NOT5 C-terminal | O75175 |
| PF04170 | NlpE | NlpE N-terminal domain | P29722 |
| PF04245 | NA37 | 37-kD nucleoid-associated bacterial protein | |
| PF04248 | NTP_transf_9 | Domain of unknown function (DUF427) | Q3J512 |
| PF04319 | NifZ | NifZ domain | |
| PF04400 | NqrM | (Na+)-NQR maturation NqrM | |
| PF04485 | NblA | Phycobilisome degradation protein nblA | P35087 |
| PF04768 | NAT | NAT, N-acetyltransferase, of N-acetylglutamate synthase | Q87EL2 |
| PF04800 | NDUS4 | NADH dehydrogenase ubiquinone Fe-S protein 4 | A0A1S3UIW7 |
| PF04880 | NUDE_C | NUDE protein, C-terminal conserved region | Q78PB6 |
| PF04891 | NifQ | NifQ | |
| PF04894 | Nre_N | Archaeal Nre, N-terminal | |
| PF04895 | Nre_C | Archaeal Nre, C-terminal | |
| PF04902 | Nab1 | Conserved region in Nab1 | |
| PF04905 | NCD2 | NAB conserved region 2 (NCD2) | Q13506 |
| PF04923 | Ninjurin | Ninjurin | |
| PF04973 | NMN_transporter | Nicotinamide mononucleotide transporter | D2ZZC1 |
| PF04981 | NMD3 | NMD3 family | P38861 |
| PF05014 | Nuc_deoxyrib_tr | Nucleoside 2-deoxyribosyltransferase | Q6AQB0 |
| PF05021 | NPL4 | NPL4 family | P33755 |
| PF05031 | NEAT | Iron Transport-associated domain | Q931P4 |
| PF05048 | NosD | Periplasmic copper-binding protein (NosD) | P19843 |
| PF05064 | Nsp1_C | Nsp1-like C-terminal region | P14907 |
| PF05071 | NDUFA12 | NADH ubiquinone oxidoreductase subunit NDUFA12 | A0A1S3VNK7 |
| PF05089 | NAGLU | Alpha-N-acetylglucosaminidase (NAGLU) tim-barrel domain | A0A0H2YU91 |
| PF05211 | NLBH | Neuraminyllactose-binding hemagglutinin precursor (NLBH) | O25166 |
| PF05224 | NDT80_PhoG | NDT80 / PhoG like DNA-binding family | Q9Y2G1 |
| PF05322 | NinE | NINE Protein | |
| PF05368 | NmrA | NmrA-like family | P34943 |
| PF05401 | NodS | Nodulation protein S (NodS) | Q880M1 |
| PF05450 | Nicastrin | Nicastrin large lobe | Q92542 |
| PF05531 | NPV_P10 | Nucleopolyhedrovirus P10 protein | |
| PF05536 | Neurochondrin | Neurochondrin | |
| PF05573 | NosL | NosL | Q52529 |
| PF05616 | Neisseria_TspB | Neisseria meningitidis TspB protein | |
| PF05630 | NPP1 | Necrosis inducing protein (NPP1) | H6W1B5 |
| PF05640 | NKAIN | Na,K-Atpase Interacting protein | |
| PF05670 | NFACT-R_1 | NFACT protein RNA binding domain | Q12532 |
| PF05676 | NDUF_B7 | NADH-ubiquinone oxidoreductase B18 subunit (NDUFB7) | A0A1S3V2B8 |
| PF05729 | NACHT | NACHT domain | Q96P20 |
| PF05766 | NinG | Bacteriophage Lambda NinG protein | |
| PF05772 | NinB | NinB protein | P03765 |
| PF05806 | Noggin | Noggin | Q13253 |
| PF05810 | NinF | NinF protein | |
| PF05819 | NolX | NolX protein | |
| PF05821 | NDUF_B8 | NADH-ubiquinone oxidoreductase ASHI subunit (CI-ASHI or NDUFB8) | Q9W3X7 |
| PF05830 | NodZ | Nodulation protein Z (NodZ) | Q9AQ17 |
| PF05833 | NFACT_N | NFACT N-terminal and middle domains | Q12532 |
| PF05896 | NQRA_N | NqrA N-terminal barrel-sandwich hybrid domain | A0A2D2BC37 |
| PF05940 | NnrS | NnrS protein | |
| PF05991 | NYN_YacP | YacP-like NYN domain | P37574 |
| PF05997 | Nop52 | Nucleolar protein,Nop52 | Q9Y7M6 |
| PF06042 | NTP_transf_6 | Nucleotidyltransferase | A0A0H2UN86 |
| PF06047 | Nkap_C | NF-kappa-B-activating protein C-terminal domain | Q8N5F7 |
| PF06119 | NIDO | Nidogen-like | |
| PF06218 | NPR2 | Nitrogen permease regulator 2 | Q8WTW4 |
| PF06235 | NAD4L | NADH dehydrogenase subunit 4L (NAD4L) | |
| PF06311 | NumbF | NUMB domain | Q9QZS3 |
| PF06312 | Neurexophilin | Neurexophilin | Q63366 |
| PF06374 | NDUF_C2 | NADH-ubiquinone oxidoreductase subunit b14.5b (NDUFC2) | Q9VQM2 |
| PF06390 | NESP55 | Neuroendocrine-specific golgi protein P55 (NESP55) | |
| PF06409 | NPIP | Nuclear pore complex interacting protein (NPIP) | |
| PF06413 | Neugrin | Neugrin | |
| PF06444 | NADH_dehy_S2_C | NADH dehydrogenase subunit 2 C-terminus | P03896 |
| PF06450 | NhaB | Bacterial Na+/H+ antiporter B (NhaB) | |
| PF06455 | NADH5_C | NADH dehydrogenase subunit 5 C-terminus | P29388 |
| PF06512 | Na_trans_assoc | Sodium ion transport-associated | Q9UQD0 |
| PF06516 | NUP | Purine nucleoside permease (NUP) | |
| PF06524 | NOA36 | NOA36 protein | |
| PF06532 | NrsF | Negative regulator of sigma F | |
| PF06567 | Neural_ProG_Cyt | Neural chondroitin sulphate proteoglycan cytoplasmic domain | |
| PF06583 | Neogenin_C | Neogenin C-terminus | |
| PF06614 | Neuromodulin | Neuromodulin | |
| PF06796 | NapE | Periplasmic nitrate reductase protein NapE | |
| PF06809 | NPDC1 | Neural proliferation differentiation control-1 protein (NPDC1) | |
| PF06813 | Nodulin-like | Nodulin-like | |
| PF06816 | NOD | NOTCH protein | Q01705 |
| PF06858 | NOG1 | Nucleolar GTP-binding protein 1 (NOG1) | O94659 |
| PF06941 | NT5C | 5' nucleotidase, deoxy (Pyrimidine), cytosolic type C protein (NT5C) | Q8TCD5 |
| PF06965 | Na_H_antiport_1 | Na+/H+ antiporter 1 | P13738 |
| PF06988 | NifT | NifT/FixU protein | Q6N0Y6 |
| PF07009 | NusG_II | NusG domain II | Q82Z21 |
| PF07075 | NamZ_N | Exo-beta-N-acetylmuramidase NamZ, N-terminal | A0A380YTY6 |
| PF07127 | Nodulin_late | Late nodulin domain | A0A0U8SNQ0 |
| PF07177 | Neuralized | Neuralized | P29503 |
| PF07225 | NDUF_B4 | NADH-ubiquinone oxidoreductase B15 subunit (NDUFB4) | Q6IDF5 |
| PF07267 | Nucleo_P87 | Nucleopolyhedrovirus capsid protein P87 | |
| PF07292 | NID | Nmi/IFP 35 domain (NID) | |
| PF07298 | NnrU | NnrU protein | |
| PF07327 | Neuroparsin | Neuroparsin | |
| PF07391 | NPR | NPR nonapeptide repeat (2 copies) | |
| PF07399 | Na_H_antiport_3 | Putative Na+/H+ antiporter | |
| PF07406 | NICE-3 | NICE-3 protein | |
| PF07453 | NUMOD1 | NUMOD1 domain | |
| PF07460 | NUMOD3 | NUMOD3 motif | |
| PF07461 | NADase_NGA | Nicotine adenine dinucleotide glycohydrolase (NADase) | D7S0C0 |
| PF07463 | NUMOD4 | NUMOD4 motif | P34081 |
| PF07479 | NAD_Gly3P_dh_C | NAD-dependent glycerol-3-phosphate dehydrogenase C-terminus | P21695 |
| PF07540 | NOC3p | Nucleolar complex-associated protein | O94288 |
| PF07555 | NAGidase | beta-N-acetylglucosaminidase | Q89ZI2 |
| PF07562 | NCD3G | Nine Cysteines Domain of family 3 GPCR | Q14832 |
| PF07575 | Nucleopor_Nup85 | Nup85 Nucleoporin | Q68FJ0 |
| PF07662 | Nucleos_tra2_C | Na+ dependent nucleoside transporter C-terminus | Q9HAS3 |
| PF07684 | NODP | NOTCH protein | Q01705 |
| PF07767 | Nop53 | Nop53 (60S ribosomal biogenesis) | Q12080 |
| PF07806 | Nod_GRP | Nodule-specific GRP repeat | |
| PF07862 | Nif11 | Nif11 domain | |
| PF07923 | N1221 | N1221-like protein | Q5VSL9 |
| PF07924 | NuiA | Nuclease A inhibitor-like protein | Q7A260 |
| PF07963 | N_methyl | Prokaryotic N-terminal methylation motif | Q74D23 |
| PF07978 | NIPSNAP | NIPSNAP | Q13PY7 |
| PF07984 | NTP_transf_7 | Nucleotidyltransferase | Q5SSF7 |
| PF07990 | NABP | Nucleic acid binding protein NABP | |
| PF07993 | NAD_binding_4 | Male sterility protein | A0A0B0DIR3 |
| PF07994 | NAD_binding_5 | Myo-inositol-1-phosphate synthase | Q8A7J8 |
| PF08030 | NAD_binding_6 | Ferric reductase NAD binding domain | P04839 |
| PF08040 | NADH_oxidored | MNLL subunit | Q9W3N7 |
| PF08058 | NPCC | Nuclear pore complex component | |
| PF08062 | NOP2_rpt | NOP2 repeat | |
| PF08075 | NOPS | NOPS (NUC059) domain | P23246 |
| PF08122 | NDUF_B12 | NADH-ubiquinone oxidoreductase B12 subunit family | A0A1S3UVV0 |
| PF08153 | NGP1NT | NGP1NT (NUC091) domain | P53742 |
| PF08154 | NLE | NLE (NUC135) domain | Q9URY0 |
| PF08155 | NOGCT | NOGCT (NUC087) domain | O94659 |
| PF08156 | NOP5NT | NOP5NT (NUC127) domain | A6ZPE5 |
| PF08157 | NUC129 | NUC129 domain | Q9UMY1 |
| PF08159 | NUC153 | NUC153 domain | Q9BSC4 |
| PF08168 | NOL11_N | Nucleolar protein 11 N-terminal domain | |
| PF08305 | NPCBM | NPCBM/NEW2 domain | A0A0H2YN38 |
| PF08376 | NIT | Nitrate and nitrite sensing | Q48468 |
| PF08378 | NERD | Nuclease-related domain | |
| PF08384 | NPP | Pro-opiomelanocortin, N-terminal region | |
| PF08414 | NADPH_Ox | Respiratory burst NADPH oxidase | Q5ZAJ0 |
| PF08424 | NRDE-2 | NRDE-2, necessary for RNA interference | |
| PF08470 | NTNH_C | Nontoxic nonhaemagglutinin C-terminal | A0A0X1KH90 |
| PF08529 | NusA_N | NusA N-terminal domain | P0AFF6 |
| PF08537 | NBP1 | Fungal Nap binding protein NBP1 | |
| PF08599 | Nbs1_C | DNA damage repair protein Nbs1 | O60934 |
| PF08600 | NuBaID_C | NuBaID, C-terminal domain | |
| PF08604 | Nup153 | Nucleoporin Nup153-like | |
| PF08619 | Nha1_C | Alkali metal cation/H+ antiporter Nha1 C terminus | |
| PF08628 | Nexin_C | Sorting nexin C terminal | |
| PF08637 | NCA2 | ATP synthase regulation protein NCA2 | |
| PF08691 | Nse5 | DNA repair proteins Nse5 and Nse6 | P40026 |
| PF08712 | Nfu_N | Scaffold protein Nfu/NifU N terminal | A0A0H3JRL4 |
| PF08719 | NADAR | NADAR domain | P30176 |
| PF08743 | Nse4_C | Nse4 C-terminal | P43124 |
| PF08744 | NOZZLE | Plant transcription factor NOZZLE | |
| PF08753 | NikR_C | NikR C terminal nickel binding domain | O25896 |
| PF08780 | NTase_sub_bind | Nucleotidyltransferase substrate binding protein like | Q5SM95 |
| PF08788 | NHR2 | NHR2 domain like | Q06455 |
| PF08801 | Nucleoporin_N | Nup133 N terminal like | P38181 |
| PF08815 | Nuc_rec_co-act | Nuclear receptor coactivator | Q9Y6Q9 |
| PF08911 | NUP50 | NUP50 (Nucleoporin 50 kDa) | Q9UKX7 |
| PF08961 | NRBF2 | Nuclear receptor-binding factor 2, autophagy regulator | |
| PF08995 | NIP_1 | Necrosis inducing protein-1 | Q02039 |
| PF09015 | NgoMIV_restric | NgoMIV restriction enzyme | P31032 |
| PF09084 | NMT1 | NMT1/THI5 like | Q187U0 |
| PF09112 | N-glycanase_N | Peptide-N-glycosidase F, N terminal | U6RE59 |
| PF09113 | N-glycanase_C | Peptide-N-glycosidase F, C terminal | U6RE59 |
| PF09126 | NaeI | Restriction endonuclease NaeI | P50187 |
| PF09292 | Neil1-DNA_bind | Endonuclease VIII-like 1, DNA bind | Q96FI4 |
| PF09296 | NUDIX-like | NADH pyrophosphatase-like rudimentary NUDIX domain | Q9BQG2 |
| PF09326 | NADH_dhqG_C | NADH-ubiquinone oxidoreductase subunit G, C-terminal | A0A1S3TQ85 |
| PF09340 | NuA4 | Histone acetyltransferase subunit NuA4 | P47128 |
| PF09376 | NurA | NurA domain | Q9RW33 |
| PF09383 | NIL | NIL domain | P30750 |
| PF09420 | Nop16 | Ribosome biogenesis protein Nop16 | Q9Y7Z1 |
| PF09426 | Nyv1_longin | Vacuolar R-SNARE Nyv1, longin domain | Q12255 |
| PF09531 | Ndc1_Nup | Nucleoporin protein Ndc1-Nup | Q6AX31 |
| PF09655 | Nitr_red_assoc | Conserved nitrate reductase-associated protein (Nitr_red_assoc) | |
| PF09735 | Nckap1 | Nck-associated protein 1 | Q9Y2A7 |
| PF09745 | NSRP1_N | Nuclear speckle splicing regulatory protein 1, N-terminal | |
| PF09764 | Nt_Gln_amidase | N-terminal glutamine amidase | Q96HA8 |
| PF09781 | NDUF_B5 | NADH:ubiquinone oxidoreductase, NDUFB5/SGDH subunit | Q9VTU2 |
| PF09782 | NDUF_B6 | NADH:ubiquinone oxidoreductase, NDUFB6/B17 subunit | Q9V3W2 |
| PF09797 | NatB_MDM20 | N-acetyltransferase B complex (NatB) non catalytic subunit | Q12387 |
| PF09805 | Nop25 | Nucleolar protein 12 (25kDa) | A0A6A5Q2X9 |
| PF09992 | NAGPA | Phosphodiester glycosidase | A0A1L8HDP6 |
| PF10125 | NADHdeh_related | NADH dehydrogenase I, subunit N related protein | |
| PF10126 | Nit_Regul_Hom | Uncharacterized protein, homolog of nitrogen regulatory protein PII | |
| PF10168 | Nup88 | Nuclear pore component | Q4KLQ6 |
| PF10176 | NEDD4_Bsd2 | NEDD4/Bsd2 | |
| PF10179 | NDNF | Neuron-derived neurotrophic factor, first Fn(III) domain | |
| PF10200 | Ndufs5 | NADH:ubiquinone oxidoreductase, NDUFS5-15kDa | Q9LZI6 |
| PF10225 | NEMP | NEMP family | |
| PF10237 | N6-adenineMlase | Probable N6-adenine methyltransferase | Q9H5U6 |
| PF10249 | NDUFB10 | NADH-ubiquinone oxidoreductase subunit 10 | Q94C12 |
| PF10309 | NCBP3 | Nuclear cap-binding protein subunit 3 | |
| PF10358 | NT-C2 | N-terminal C2 in EEIG1 and EHBP1 proteins | |
| PF10364 | NKWYS | Putative capsular polysaccharide synthesis protein | |
| PF10379 | nec1 | Virulence protein nec1 | |
| PF10444 | Nbl1_Borealin_N | Nbl1 / Borealin N terminal | Q53HL2 |
| PF10453 | NUFIP1 | FMR1-interacting protein 1 (NUFIP1) | Q08932 |
| PF10487 | Nup188_N | Nucleoporin Nup188, N-terminal | P52593 |
| PF10491 | Nrf1_DNA-bind | NLS-binding and DNA-binding and dimerisation domains of Nrf1 | |
| PF10492 | Nrf1_activ_bdg | Nrf1 activator activation site binding domain | |
| PF10505 | NARG2_C | NMDA receptor-regulated gene protein 2 C-terminus | |
| PF10524 | NfI_DNAbd_pre-N | Nuclear factor I protein pre-N-terminus | Q14938 |
| PF10565 | NMDAR2_C | N-methyl D-aspartate receptor 2B3 C-terminus | |
| PF10567 | Nab6_mRNP_bdg | RNA-recognition motif | |
| PF10580 | Neuromodulin_N | Gap junction protein N-terminal region | |
| PF10588 | NADH-G_4Fe-4S_3 | NADH-ubiquinone oxidoreductase-G iron-sulfur binding region | A0QU30 |
| PF10589 | NADH_4Fe-4S | NADH-ubiquinone oxidoreductase-F iron-sulfur binding region | A0QU31 |
| PF10599 | Nup_retrotrp_bd | Retro-transposon transporting motif | |
| PF10633 | NPCBM_assoc | NPCBM-associated, NEW3 domain of alpha-galactosidase | Q02834 |
| PF10664 | NdhM | Cyanobacterial and plastid NDH-1 subunit M | Q2V2S7 |
| PF10712 | NAD-GH | NAD-specific glutamate dehydrogenase | |
| PF10716 | NdhL | NADH dehydrogenase transmembrane subunit | Q9CAC5 |
| PF10785 | NADH-u_ox-rdase | NADH-ubiquinone oxidoreductase complex I, 21 kDa subunit | A0A1S3VI15 |
| PF10863 | NOP19 | Nucleolar protein 19 | |
| PF11030 | Nucleocapsid-N | Nucleocapsid protein N | |
| PF11071 | Nuc_deoxyri_tr3 | Nucleoside 2-deoxyribosyltransferase YtoQ | |
| PF11073 | NSs | Rift valley fever virus non structural protein (NSs) like | P12792 |
| PF11438 | N36 | 36-mer N-terminal peptide of the N protein (N36) | P03045 |
| PF11497 | NADH_Oxid_Nqo15 | NADH-quinone oxidoreductase chain 15 | Q5SKZ7 |
| PF11517 | Nab2 | Nuclear abundant poly(A) RNA-bind protein 2 (Nab2) | P32505 |
| PF11537 | NitrOD5 | Nitrosopumilus output domain 5 | O58562 |
| PF11577 | NEMO | NF-kappa-B essential modulator NEMO | Q9Y6K9 |
| PF11623 | NdhS | NAD(P)H dehydrogenase subunit S | Q8DL61 |
| PF11654 | NCE101 | Non-classical export protein 1 | |
| PF11707 | Npa1 | Ribosome 60S biogenesis N-terminal | |
| PF11733 | NP1-WLL | Non-capsid protein NP1 | |
| PF11764 | N-SET | COMPASS (Complex proteins associated with Set1p) component N | P38827 |
| PF11825 | Nuc_recep-AF1 | Nuclear/hormone receptor activator site AF-1 | P19793 |
| PF11894 | Nup192 | Nuclear pore complex scaffold, nucleoporins 186/192/205 | P47054 |
| PF11909 | NdhN | NADH-quinone oxidoreductase cyanobacterial subunit N | Q9LVM2 |
| PF11910 | NdhO | Cyanobacterial and plant NDH-1 subunit O | A0A178WB24 |
| PF11923 | NFACT-C | NFACT protein C-terminal domain | Q12532 |
| PF11933 | Na_trans_cytopl | Cytoplasmic domain of voltage-gated Na+ ion channel | Q9UQD0 |
| PF11939 | NiFe-hyd_HybE | [NiFe]-hydrogenase assembly, chaperone, HybE | P0AAN1 |
| PF11973 | NQRA_SLBB | NQRA C-terminal domain | A0A2D2BC37 |
| PF12061 | NB-LRR | Late blight resistance protein R1 | |
| PF12110 | Nup96 | Nuclear protein 96 | A0A1B8XZT4 |
| PF12183 | NotI | Restriction endonuclease NotI | |
| PF12281 | NTP_transf_8 | Nucleotidyltransferase | |
| PF12308 | Noelin-1 | Neurogenesis glycoprotein | O88998 |
| PF12313 | NPR1_like_C | NPR1/NIM1 like defence protein C terminal | P93002 |
| PF12402 | nlz1 | NocA-like zinc-finger protein 1 | |
| PF12533 | Neuro_bHLH | Neuronal helix-loop-helix transcription factor | |
| PF12535 | Nudix_N | Hydrolase of X-linked nucleoside diphosphate N terminal | Q81EE8 |
| PF12569 | NatA_aux_su | N-terminal acetyltransferase A, auxiliary subunit | Q9BXJ9 |
| PF12622 | NpwBP | mRNA biogenesis factor | |
| PF12667 | NigD_N | NigD-like N-terminal OB domain | A5ZGW9 |
| PF12753 | Nro1 | Nuclear pore complex subunit Nro1 | Q9USJ7 |
| PF12804 | NTP_transf_3 | MobA-like NTP transferase domain | A6TG34 |
| PF12830 | Nipped-B_C | Sister chromatid cohesion C-terminus | Q04002 |
| PF12853 | NADH_u_ox_C | C-terminal of NADH-ubiquinone oxidoreductase 21 kDa subunit | G0S0S8 |
| PF12881 | NUT | NUT protein | |
| PF12912 | N_NLPC_P60 | NLPC_P60 stabilising domain, N term | A0A1V1VDL8 |
| PF12971 | NAGLU_N | Alpha-N-acetylglucosaminidase (NAGLU) N-terminal domain | A0A0H2YU91 |
| PF12972 | NAGLU_C | Alpha-N-acetylglucosaminidase (NAGLU) C-terminal domain | A0A0H2YU91 |
| PF13006 | Nterm_IS4 | Insertion element 4 transposase N-terminal | |
| PF13020 | NOV_C | Protein NO VEIN, C-terminal | |
| PF13241 | NAD_binding_7 | Putative NAD(P)-binding | P25924 |
| PF13283 | NfrA_C | Bacteriophage N adsorption protein A C-term | |
| PF13379 | NMT1_2 | NMT1-like family | Q2G1I5 |
| PF13450 | NAD_binding_8 | NAD(P)-binding Rossmann-like domain | M1VMF7 |
| PF13454 | NAD_binding_9 | FAD-NAD(P)-binding | |
| PF13460 | NAD_binding_10 | NAD(P)H-binding | Q9SK66 |
| PF13562 | NTP_transf_4 | Sugar nucleotidyl transferase | |
| PF13597 | NRDD | Anaerobic ribonucleoside-triphosphate reductase | Q9WYL6 |
| PF13634 | Nucleoporin_FG | Nucleoporin FG repeat region | P48837 |
| PF13726 | Na_H_antiport_2 | Na+-H+ antiporter family | |
| PF13820 | NCOA6_TRADD-N | Nuclear receptor coactivator 6, TRADD-N domain | |
| PF13869 | NUDIX_2 | Nucleotide hydrolase | O43809 |
| PF13874 | Nup54 | Nucleoporin complex subunit 54 | P48837 |
| PF13945 | NST1 | Salt tolerance down-regulator | |
| PF14044 | NETI | NETI protein | |
| PF14046 | NR_Repeat | Nuclear receptor repeat | Q61066 |
| PF14050 | Nudc_N | N-terminal conserved domain of Nudc. | |
| PF14055 | NVEALA | NVEALA protein | |
| PF14303 | NAM-associated | No apical meristem-associated C-terminal domain | |
| PF14365 | Neprosin_AP | Neprosin activation peptide | A0A1L7NZU4 |
| PF14448 | Nuc_N | Nuclease N terminal | |
| PF14465 | NFRKB_winged | NFRKB Winged Helix-like | Q6P4R8 |
| PF14496 | NEL | C-terminal novel E3 ligase, LRR-interacting | D2AJU0 |
| PF14540 | NTF-like | Nucleotidyltransferase-like | B1YK61 |
| PF14589 | NrfD_2 | Polysulfide reductase | Q72LA6 |
| PF14605 | Nup35_RRM_2 | Nup53/35/40-type RNA recognition motif | |
| PF14710 | Nitr_red_alph_N | Respiratory nitrate reductase alpha N-terminal | P09152 |
| PF14711 | Nitr_red_bet_C | Respiratory nitrate reductase beta C-terminal | P11349 |
| PF14720 | NiFe_hyd_SSU_C | NiFe/NiFeSe hydrogenase small subunit C-terminal | I7G634 |
| PF14736 | N_Asn_amidohyd | Protein N-terminal asparagine amidohydrolase | Q96AB6 |
| PF14755 | Nsp2_AV | Nsp2, transmembrane domain | |
| PF14772 | NYD-SP28 | Sperm tail | A8JB22 |
| PF14775 | NYD-SP28_assoc | Sperm tail C-terminal domain | A8JB22 |
| PF14780 | NEPRO_N | Nucleolus and neural progenitor protein, N-terminal | |
| PF14813 | NADH_B2 | NADH dehydrogenase 1 beta subcomplex subunit 2 | Q7PL91 |
| PF14815 | NUDIX_4 | NUDIX domain | P83847 |
| PF14833 | NAD_binding_11 | NAD-binding of NADP-dependent 3-hydroxyisobutyrate dehydrogenase | C9ZJW2 |
| PF14907 | NTP_transf_5 | Uncharacterised nucleotidyltransferase | |
| PF14927 | Neurensin | Neurensin/Transmembrane protein 74 | |
| PF14987 | NADHdh_A3 | NADH dehydrogenase 1 alpha subcomplex subunit 3 | A0A4X1VQ42 |
| PF14993 | Neuropeptide_S | Neuropeptide S precursor protein | |
| PF15015 | NYD-SP12_N | Spermatogenesis-associated, N-terminal | |
| PF15053 | Njmu-R1 | Njmu-R1-like protein family | |
| PF15056 | NRN1 | Neuritin protein family | |
| PF15065 | NCU-G1 | Lysosomal transcription factor, NCU-G1 | Q9JHJ3 |
| PF15085 | NPFF | Neuropeptide FF | |
| PF15088 | NADH_dh_m_C1 | NADH dehydrogenase [ubiquinone] 1 subunit C1, mitochondrial | A0A6P3EDV0 |
| PF15161 | Neuropep_like | Neuropeptide-like | |
| PF15180 | NPBW | Neuropeptides B and W | |
| PF15246 | NCKAP5 | Nck-associated protein 5, Peripheral clock protein | |
| PF15273 | NHS | NHS-like protein | |
| PF15293 | NUFIP2 | FMR1-interacting protein 2 | |
| PF15370 | NOPCHAP1 | NOP protein chaperone 1 | |
| PF15412 | Nse4-Nse3_bdg | Binding domain of Nse4/EID3 to Nse3-MAGE | P43124 |
| PF15439 | NYAP_N | Neuronal tyrosine-phosphorylated phosphoinositide-3-kinase adapter | |
| PF15447 | NTS | N-terminal segments of PfEMP1 | B7T1P0 |
| PF15448 | NTS_2 | N-terminal segments of P. falciparum erythrocyte membrane protein | A0A024V5I6 |
| PF15452 | NYAP_C | Neuronal tyrosine-phosphorylated phosphoinositide-3-kinase adapter | |
| PF15458 | NTR2 | Nineteen complex-related protein 2 | P36118 |
| PF15492 | Nbas_N | Neuroblastoma-amplified sequence, N terminal | |
| PF15500 | Ntox1 | Putative RNase-like toxin, toxin_1 | |
| PF15508 | NAAA-beta | beta subunit of N-acylethanolamine-hydrolyzing acid amidase | Q13510 |
| PF15520 | Ntox10 | Novel toxin 10 | |
| PF15521 | Ntox11 | Novel toxin 11 | |
| PF15522 | Ntox14 | Novel toxin 14 | |
| PF15523 | Ntox16 | Novel toxin 16 | |
| PF15524 | Ntox17 | Novel toxin 17 | |
| PF15526 | Ntox21 | Novel toxin 21 | D5CBA0 |
| PF15527 | Ntox22 | Bacterial toxin 22 | |
| PF15528 | Ntox23 | Bacterial toxin 23 | |
| PF15529 | Ntox24 | Bacterial toxin 24 | |
| PF15530 | Ntox25 | Bacterial toxin 25 | |
| PF15531 | Ntox27 | Bacterial toxin 27 | |
| PF15532 | Ntox30 | Bacterial toxin 30 | |
| PF15533 | Ntox33 | Bacterial toxin 33 | |
| PF15534 | Ntox35 | Bacterial toxin 35 | |
| PF15535 | Ntox37 | Bacterial toxin 37 | |
| PF15536 | Ntox3 | Bacterial toxin 3 | |
| PF15537 | Ntox43 | Bacterial toxin 43 | |
| PF15538 | Ntox46 | Bacterial toxin 46 | Q9I739 |
| PF15540 | Ntox47 | Bacterial toxin 47 | |
| PF15541 | Ntox4 | Bacterial toxin 4 | |
| PF15542 | Ntox50 | Bacterial toxin 50 | |
| PF15543 | Ntox5 | Bacterial toxin 5 | |
| PF15544 | Ntox6 | Bacterial toxin 6 | |
| PF15545 | Ntox8 | Bacterial toxin 8 | |
| PF15604 | Ntox15 | Novel toxin 15 | |
| PF15605 | Ntox28 | Bacterial toxin 28 | Q0T963 |
| PF15606 | Ntox34 | Bacterial toxin 34 | |
| PF15607 | Ntox44 | Bacterial toxin 44 | |
| PF15687 | NRIP1_repr_1 | Nuclear receptor-interacting protein 1 repression 1 | |
| PF15688 | NRIP1_repr_2 | Nuclear receptor-interacting protein 1 repression 2 | |
| PF15689 | NRIP1_repr_3 | Nuclear receptor-interacting protein 1 repression 3 | |
| PF15690 | NRIP1_repr_4 | Nuclear receptor-interacting protein 1 repression 4 | |
| PF15692 | NKAP | NF-kappa-B-activating protein | Q8N5F7 |
| PF15699 | NPR1_interact | NPR1 interacting | |
| PF15712 | NPAT_C | NPAT C terminus | |
| PF15845 | NICE-1 | Cysteine-rich C-terminal 1 family | |
| PF15880 | NDUFV3 | NADH dehydrogenase [ubiquinone] flavoprotein 3, mitochondrial | Q9VZ01 |
| PF15891 | Nuc_deoxyri_tr2 | Nucleoside 2-deoxyribosyltransferase like | A6L9R1 |
| PF15967 | Nucleoporin_FG2 | Nucleoporin FG repeated region | Q5EAX5 |
| PF16006 | NUSAP | Nucleolar and spindle-associated protein | |
| PF16136 | NLS_NINJA_AFP | Putative nuclear localisation signal in Ninja/AFP proteins | |
| PF16158 | N_BRCA1_IG | Ig-like domain from next to BRCA1 gene | G0SE85 |
| PF16201 | NopRA1 | Nucleolar pre-ribosomal-associated protein 1 | |
| PF16273 | NuDC | Nuclear distribution C domain | Q9Y266 |
| PF16276 | NPM1-C | Nucleophosmin C-terminal domain | P06748 |
| PF16414 | NPC1_N | Niemann-Pick C1 N terminus | Q9UHC9 |
| PF16469 | NPA | Nematode polyprotein allergen ABA-1 | Q06811 |
| PF16494 | Na_Ca_ex_C | C-terminal extension of sodium/calcium exchanger domain | P23685 |
| PF16508 | NIBRIN_BRCT_II | Second BRCT domain on Nijmegen syndrome breakage protein | O60934 |
| PF16514 | NADH-UOR_E | putative NADH-ubiquinone oxidoreductase chain E | O25854 |
| PF16517 | Nore1-SARAH | Novel Ras effector 1 C-terminal SARAH (Sav/Rassf/Hpo) domain | Q8WWW0 |
| PF16601 | NPF | Rabosyn-5 repeating NPF sequence-motif | |
| PF16621 | NCF1_PBR_AIR | Neutrophil cytosol factor 1, PBR/AIR | P14598 |
| PF16644 | NEXCaM_BD | Regulatory region of Na+/H+ exchanger NHE binds to calmodulin | P19634 |
| PF16665 | NCOA_u2 | Unstructured region on nuclear receptor coactivator protein | |
| PF16705 | NUDIX_5 | NUDIX, or N-terminal NPxY motif-rich, region of KRIT | O00522 |
| PF16725 | Nucleolin_bd | Nucleolin binding domain | Q9DBY8 |
| PF16733 | NRho | Rhomboid N-terminal domain | Q9HZC2 |
| PF16768 | NupH_GANP | Nucleoporin homology of Germinal-centre associated nuclear protein | |
| PF16787 | NDC10_II | Centromere DNA-binding protein complex CBF3 subunit, domain 2 | Q6CPM4 |
| PF16809 | NleF_casp_inhib | NleF caspase inhibitor | Q8XAL7 |
| PF16830 | NBD94 | Nucleotide-Binding Domain 94 of RH | |
| PF16868 | NMT1_3 | NMT1-like family | Q2GGH8 |
| PF16974 | NAR2 | High-affinity nitrate transporter accessory, Ig-like domain | |
| PF17042 | NBD_C | Nucleotide-binding C-terminal domain | Q0KBC8 |
| PF17100 | NACHT_N | N-terminal domain of NWD NACHT-NTPase | |
| PF17106 | NACHT_sigma | Sigma domain on NACHT-NTPases | |
| PF17114 | Nod1 | Gef2-related medial cortical node protein Nod1 | |
| PF17169 | NRBF2_MIT | MIT domain of nuclear receptor-binding factor 2 | Q96F24 |
| PF17185 | NlpE_C | NlpE C-terminal OB domain | P40710 |
| PF17238 | NUP160_helical_2 | NUP160, helical domain | |
| PF17250 | NDUFB11 | NADH-ubiquinone oxidoreductase 11 kDa subunit | A0A1S3U2B9 |
| PF17367 | NiFe_hyd_3_EhaA | NiFe-hydrogenase-type-3 Eha complex subunit A | |
| PF17398 | NolB | Nodulation protein NolB | |
| PF17403 | Nrap_D2 | Nrap protein PAP/OAS-like domain | P53254 |
| PF17404 | Nrap_D3 | Nrap protein domain 3 | P53254 |
| PF17405 | Nrap_D4 | Nrap protein nucleotidyltransferase domain 4 | P53254 |
| PF17406 | Nrap_D5 | Nrap protein PAP/OAS1-like domain 5 | P53254 |
| PF17407 | Nrap_D6 | Nrap protein domain 6 | P53254 |
| PF17415 | NigD_C | NigD-like C-terminal beta sandwich domain | A5ZGW9 |
| PF17466 | NinD | Family of unknown function | |
| PF17767 | NAPRTase_N | Nicotinate phosphoribosyltransferase (NAPRTase) N-terminal domain | Q6XQN6 |
| PF17776 | NLRC4_HD2 | NLRC4 helical domain HD2 | Q96P20 |
| PF17779 | NOD2_WH | NOD2 winged helix domain | Q96P20 |
| PF17800 | NPL | Nucleoplasmin-like domain | F4J9Q6 |
| PF17835 | NOG1_N | NOG1 N-terminal helical domain | O94659 |
| PF17889 | NLRC4_HD | NLRC4 helical domain | Q9R016 |
| PF17956 | NAPRTase_C | Nicotinate phosphoribosyltransferase C-terminal domain | Q6XQN6 |
| PF18068 | Npun_R1517 | Npun R1517 | B2IZS7 |
| PF18082 | NAT_N | N-acyltransferase N-terminal domain | Q70AY4 |
| PF18127 | NAMPT_N | Nicotinamide phosphoribosyltransferase, N-terminal domain | P43490 |
| PF18208 | NES_C_h | Nicking enzyme C-terminal middle helical domain | |
| PF18216 | N_formyltrans_C | N-formyltransferase dimerization C-terminal domain | A0A0N8R1B2 |
| PF18260 | Nab2p_Zf1 | Nuclear polyadenylated RNA-binding 2 protein CCCH zinc finger 1 | P32505 |
| PF18265 | Nas2_N | Nas2 N_terminal domain | P40555 |
| PF18266 | Ncstrn_small | Nicastrin small lobe | Q92542 |
| PF18290 | Nudix_hydro | Nudix hydrolase domain | Q9SU14 |
| PF18297 | NFACT-R_2 | NFACT protein RNA binding domain | |
| PF18298 | NusG_add | NusG additional domain | P29397 |
| PF18378 | Nup188_C | Nuclear pore protein NUP188 C-terminal domain | P52593 |
| PF18413 | Neuraminidase | Neuraminidase-like domain | Q9RN43 |
| PF18437 | Nup54_C | Nup54 C-terminal interacting domain | K9ZTJ6 |
| PF18510 | NUC | Nuclease domain | A0A182DWE3 |
| PF18549 | NitrOD1 | Nitrosopumilus output domain 1 | |
| PF18550 | NitrOD2 | Nitrososphaera output domain 2 | |
| PF18557 | NepR | Anti-sigma factor NepR | A0A0H3LV19 |
| PF18570 | Nup54_57_C | NUP57/Nup54 C-terminal domain | G0S0R2 |
| PF18595 | Nuf2_DHR10-like | Nuf2, DHR10-like domain | |
| PF18617 | Nup214_FG | Nucleoporin Nup214 phenylalanine-glycine (FG) domain | P35658 |
| PF18753 | Nmad2 | Nucleotide modification associated domain 2 | |
| PF18754 | Nmad3 | Nucleotide modification associated domain 3 | |
| PF18756 | Nmad4 | Nucleotide modification associated domain 4 | |
| PF18757 | Nmad5 | Nucleotide modification associated domain 5 | |
| PF18764 | nos_propeller | Nitrous oxide reductase propeller repeat | P19573 |
| PF18778 | NAD1 | Novel AID APOBEC clade 1 | |
| PF18782 | NAD2 | Novel AID APOBEC clade 2 | M1GSK9 |
| PF18793 | nos_propeller_2 | Nitrous oxide reductase propeller repeat 2 | P19573 |
| PF19271 | Nis1 | Nis1 family | |
| PF19285 | NmU-R2_C_term | Neuromedin-U receptor 2, C-terminal | Q9GZQ4 |
| PF19312 | NtrY_N | NtrY N-terminal region | |
| PF19338 | NTF3_N | Neutrophin-3 N-terminus | |
| PF19433 | NDNF_C | Neuron-derived Neurotrophic Factor C-terminal | |
| PF19530 | Ndh2_N | NAD(P)H-quinone oxidoreductase subunit 2 N-terminal | A0A1B1W4Z4 |
| PF20143 | NAD_kinase_C | ATP-NAD kinase C-terminal domain | Q8Y8D7 |
| PF20146 | NRF | Nose resistant-to-fluoxetine protein, N-terminal domain | |
| PF20299 | NARF | Nucleotidyltransferase-Associated Rossmannoid Fold | |
| PF20425 | Neurobeachin | Neurobeachin alpha solenoid region | |
| PF20426 | NBCH_WD40 | Neurobeachin beta propeller domain | |
| PF20427 | NRP1_C | Nuclear speckle splicing regulatory protein 1, RS-like domain | |
| PF20697 | NTase-conflict | Pol beta superfamily nucleotidyltransferase in conflict systems | |
| PF20702 | nSTAND2 | Novel STAND NTPase 2 | |
| PF20703 | nSTAND1 | Novel STAND NTPase 1 | |
| PF20720 | nSTAND3 | Novel STAND NTPase 3 | |
| PF20727 | Nairovirus_MLD | Nairovirus, mucin-like domain | |
| PF20732 | NamZ_C | Exo-beta-N-acetylmuramidase NamZ, C-terminal | |
| PF20798 | NleE | Cysteine methyltransferase effector NleE | |
| PF20841 | NtrZ | NtrZ | |
| PF20885 | NPB13-l_MII_rpt | Nuclear pore complex-interacting protein B13-like, MII repeat | |
| PF20998 | Nol11_C | Nucleolar protein 11 C-terminal domain | |
| PF21003 | NucS_N | Endonuclease NucS N-terminal PH-like domain | |
| PF21006 | NHase_beta_N | Nitrile hydratase beta subunit, N-terminal | |
| PF21093 | Nup188_N-subdom_III | Nucleoporin Nup188, N-terminal subdomain III | |
| PF21094 | Nup188_SH3-like | Nup188 SH3-like domain | |
| PF21121 | Nup49_C | Nucleoporin Nup49 C-terminal helical region | |
| PF21148 | NSUN5_fdxn-like | NOL1/NOP2/Sun domain family member 5, ferredoxin-like domain | |
| PF21153 | NSUN5_N | NOL1/NOP2/Sun domain family member 5, N-terminal domain | |
| PF21192 | NMD3_OB | NMD3 OB-fold domain | |
| PF21193 | NMD_SH3 | NMD3 SH3 domain | |
| PF21230 | Nakanori | Nakanori-like protein | |
| PF21240 | Nup98_GLEBS | Nup98, Gle2-binding sequence | |
| PF21380 | Nrd1-Seb1_dom2 | Nrd1/Seb1, domain 2 | |
| PF21400 | Ndc10_N | Ndc10 N-terminal domain | |
| PF21402 | NLRX1_C | NLR family member X1, C-terminal domain | |
| PF21486 | NUP120_helical | Nucleoporin NUP120, helical domain | |
| PF21525 | Nlp36 | Neuropeptide-like peptide 36 | |
| PF21566 | NagA_C | Beta-N-acetylglucosaminidase, C-terminal domain | |
| PF21572 | Nop5_56-rel_N_Arc | Archaeal Nop5/56-rel, N-terminal domain | |
| PF21641 | NarE | NarE | |
| PF21667 | Nop5_N | Nop5, N-terminal domain | |
| PF21774 | NagJ_C | Hyaluronidase post-catalytic domain-like | |
| PF21803 | Nab2-zf4 | Nab2-type CCCH zinc finger 4 | |
| PF21827 | New_glue | New glue protein family | |
| PF21888 | NFLD | Ferredoxin-like NFLD domain | |
| PF21894 | N4_RNAP_helical | Bacteriophage N4 RNA polymerase, helical domain | |
| PF21906 | NrtR_WHD | NrtR DNA-binding winged helix domain | |
| PF21917 | NMB0537_N | N-terminal region of NMB0537 | |
| PF21949 | NoBody | Negative regulator of P-body association | |
| PF21953 | NadN_nucleosid_C | NAD nucleotidase, C-terminal domain | |
| PF21964 | NSF_ATPase_lid | NSF, AAA+ ATPase lid domain | |
| PF21983 | NikA-like | Mobilization protein NikA | |
| PF22085 | NorB_cytochrome_c-like | Nitric oxide reductase subunit B, cytochrome c-like domain | |
| PF22106 | NGO1945_C | NGO1945 C-terminal domain | |
| PF22114 | NUP120_helical_2 | Nucleoporin NUP120, helical domain | |
| PF22127 | NtdA_N | NTD biosynthesis operon protein NtdA, N-terminal domain | |
| PF22174 | NMB1110-like_C | Tail protein, C-terminal domain | |
| PF22221 | NigD_N-like | Lipoprotein BF3042 OB domain | |
| PF22300 | NGO_1070-like | NGO_1070-like | |
| PF22310 | NMB0315_dom_I | NMB0315-like, domain I | |
| PF22314 | NPC1_MLD | NPC1, middle luminal domain | |
| PF22327 | Nudt16-like | U8 snoRNA-decapping enzyme-like | |
| PF22329 | Nro1_C | Negative regulator of ofd1, C-terminal | |
| PF22366 | NDH2_C | NDH2 C-terminal domain | |
| PF22397 | NADAR-DarT1 | DarT1-associated NADAR antitoxin | |
| PF22451 | NirdL-like_HTH | Siroheme decarboxylase NirDL-like HTH domain | |
| PF22460 | Neopullulanase-like_C | Neopullulanase-like, C-terminal domain | |
| PF22524 | Nlrc4-like_WHD | Nlrc4-like, winged helix domain | |
| PF22602 | NXF_NTF2 | Nuclear RNA export factor, NTF2 domain | |
| PF22630 | NMB1110_3rd | Tail protein NMB1110-like, third domain | |
| PF22643 | NagA_N | NagA composite domain | |
| PF22683 | Nab2-like_zf-CCCH_ | Nab2-like CCCH zinc finger | |
| PF22722 | NA-iREase1 | NACHT-associated inactive Restriction Endonuclease 1 | |
| PF22723 | NA-iREase2 | NACHT-associated inactive Restriction Endonuclease 2 | |
| PF22724 | NCAB1 | NACHT C-terminal Alpha/Beta 1 | |
| PF22726 | NCAB2 | NACHT C-terminal Alpha/Beta 2 | |
| PF22727 | NCH2 | NACHT C-terminal Helical domain 2 | |
| PF22728 | NCH1 | NACHT C-terminal Helical domain 1 | |
| PF22729 | NCH3 | NACHT C-terminal Helical domain 3 | |
| PF22730 | NCC-H | NACHT C-terminal Cysteine and Histidine-containing | |
| PF22731 | NCH4 | NACHT C-terminal Helical domain 4 | |
| PF22733 | NNH1 | NACHT N-terminal Helical domain 1 | |
| PF22734 | NNH2 | NACHT N-terminal Helical domain 2 | |
| PF22735 | NNH3 | NACHT N-terminal Helical domain 3 | |
| PF22736 | NNH5 | NACHT N-terminal Helical domain 5 | |
| PF22737 | NNH6 | NACHT N-terminal Helical domain 6 | |
| PF22738 | NNH7 | NACHT N-terminal Helical domain 7 | |
| PF22739 | NA-iREase3 | NACHT-associated inactive Restriction Endonuclease 2 | |
| PF22745 | Nlig-Ia | DNA ligase-like, N-terminal NAD+-binding domain | |
| PF22761 | NrS1-1_pol-like_head | NrS-1 polymerase-like head domain | |
| PF22762 | NrS1-pol-like_tail | NrS-1 polymerase-like, tail domain | |
| PF22763 | NrS1-1_pol-like_HBD | NrS-1 polymerase HBD domain | |
| PF22898 | NOMO1-like_1st | BOS complex subunit NOMO1-like, first beta sandwich domain | |
| PF22902 | NOMO1-like_9th | BOS complex subunit NOMO1-like, beta sandwich domain | |
| PF22904 | NOMO1-like_2nd | BOS complex subunit NOMO1-like, second beta sandwich domain | |
| PF22913 | NBAS_11th | NBAS subunit of NRZ tethering complex, C-terminal | |
| PF22957 | NUP210_Ig | NUP210 Ig-like domain | |
| PF23056 | NTF2_MEX67 | MEX67-like, NTF2-like domain | |
| PF23097 | NOL10_2nd | Nucleolar protein 10-like, second domain | |
| PF23111 | N1_PEX6 | PEX6 N1 domain | |
| PF23114 | NAD-bd_HRPKS_sdrA | HRPKS sdrA-like, NAD(P)-binding Rossmann-fold domain | |
| PF23151 | NuiA_2 | NuiA-like | |
| PF23192 | NOMO_12th | NOMO C-terminal transthyretin-like domain | |
| PF23193 | NOMO_3rd | NOMO third transthyretin-like domain | |
| PF23194 | NOMO_5th | NOMO fifth transthyretin-like domain | |
| PF23196 | NOMO_6th | NOMO sixth transthyretin-like domain | |
| PF23262 | NFD4_C | NFD4, C-terminal domain | |
| PF23345 | NUP160_helical | Nucleoporin NUP160, helical domain | |
| PF23386 | NPP-6_helical | NPP-6, helical domain | |
| PF23553 | NELF-A_N | NELF-A N-terminal domain | |
| PF23569 | NBD_SMAX1 | SMAX1 nucleotide binding domain | |
| PF23590 | NOT1_connector | CCR4-NOT transcription complex subunit 1, NOT1_connector | |
| PF23660 | NOMO_8th | NOMO eighth prealbumin-like domain | |
| PF23844 | NCTSP_N | Non-contractile tail sheath N-terminal domain | |
| PF24103 | NT_N | Neurotrophin 1 N-terminal | |
| PF24179 | NTE_Ploop | Neuropathy Target Esterase family P-loop like domain | |
| PF24268 | NttC | T2SS substrate NttC | |
| PF24274 | NttE | T2SS substrate NttE | |
| PF24275 | NttA | T2SS substrate NttA | |
| PF24354 | NDNF_N | Neuron-derived neurotrophic factor, N-terminal domain | |
| PF24404 | nSTAND_NTPase7 | Novel STAND NTPase 7 | |
| PF24406 | nSTAND_NTPase4 | Novel STAND NTPase 4 | |
| PF24487 | NDC80_loop | Kinetochore protein NDC80 loop region | |
| PF24536 | NXPE4_C | NXPE family member 4-like, C-terminal domain | |
| PF24565 | Ned1_M | Nuclear elongation and deformation protein 1-like, middle domain | |
| PF24574 | Nm-ACP | ACP-like domain | |
| PF24675 | NpmA | 16S rRNA (adenine(1408)-N(1))-methyltransferase | |
| PF24679 | Nodulin_C | Nodulin C-terminal domain | |
| PF24690 | NTCP5_P3_N | NTCP5/P3 N-terminal domain | |
| PF24836 | NQRA_2nd | NqrA second alpha/beta domain | |
| PF24840 | NTF2_SigF | SigF NTF2-like domain | |