CODSWALLOP

Coagulation factor X

Homo sapiens · seed P00742 · 488 aa · family defined as ≥30% identity to that seed · compiled 07 October 2026

CATH and SCOP identifiers come from the RCSB's own structure annotations, which the Domains panel already reads, so these are looked up rather than guessed at.

1,775Entries 1,984Entities 347Constructs 16Organisms 1,614Ligand-bound
0.75 ÅBest res.
1.85 ÅMedian res.

Every figure here is counted over the whole family rather than quoted from one entry.

The reference structure

9I24, the structure every other member of this family is superposed onto. Rendered by the RCSB and embedded here: the live app shows an interactive viewport, which a document that fetches nothing cannot.

Rendered structure of 9I24
9I24 at the RCSB · open it in the 3D viewer

Which residues anyone has ever seen

How many of this family's constructs contain each residue of the seed. A trough is a stretch nobody has put in a construct, which is a construct-design answer rather than a disorder one.

12444881712 constructs

Constructs, most-used first

347 distinct constructs across 1,775 entries. 1,938 polymer entities differ from the UniProt canonical sequence in some way, 72 carry a recognised expression tag and 3 carry a fusion partner.

"Differs from canonical" is not the same as "engineered". The canonical sequence is the full gene product, so a secreted protein whose structures all start after its signal peptide counts every one of them as different: lysozyme's most-used construct, residues 19–147 on 1,239 entities, is simply the mature protein. Read the construct column below for what was actually done, rather than this count.

EntitiesLengthBest (Å)Best entryWhat was made
486 223 0.75 4I8H residues 24-246
223 259 1.12 4UD9 residues 364-622
102 254 1.36 5PAG residues 213-466
46 254 1.55 4Y6D residues 235-488
39 134 1.55 4Y6D residues 46-179
37 244 1.55 5TKS His6; residues 388-625; N491G, T493G
30 253 1.40 6XVD residues 179-431; C299A, N322Q
29 39 1.53 6YYX residues 86-124; C90S, C95S, C112S +1 more
28 234 1.50 2PR3 residues 235-468
28 238 0.92 7MBO residues 388-625; C500S
25 246 0.91 4XOJ matches the canonical sequence
23 229 1.50 1BTY residues 18-246
23 238 1.25 4CRG residues 388-625; S452A, K455A, T493A +1 more
21 152 1.40 4YLQ residues 61-212
20 52 1.54 3FFG residues 127-178
19 246 1.18 5YC6 residues 179-424; C299A, N322Q
17 245 1.45 5Z1C residues 179-423; C299A, N322Q
17 245 1.65 4MPU residues 31-275; R51H, D52G, R53P +1 more
16 55 1.25 2JKH residues 126-180
16 96 1.95 1C5M residues 84-179
16 235 1.90 1G2L residues 235-469
16 257 1.30 2CF8 residues 364-620
15 233 1.62 2P3U residues 235-467
14 243 1.15 1UTN residues 4-246
14 258 1.12 5AFY residues 364-621

Showing the 25 most-used of 347.

Positions people deliberately mutate

Columns where the wild-type residue still dominates but a real minority carries something else, which is a different question from "what varies across species".

E296V 70% R313S 70% D320N 69% F334L 68% R387D 68% T430R 68% Y449P 68% A349S 68% V382A 68% R445Q 67% S393A 67% E317N 67% K370S 64% E369S 64% R346S 63% S374P 62% S351G 62% L353Q 61% G447N 61% V305A 61% L326I 61% S267N 60% A414S 59% V385L 58% E306S 58% T355A 58% L272V 57% E441S 57% S389V 56% A339H 55%

What it assembles into

Oligomeric stateChainsEntriesShare
monomeric1 762 42.9%
dimeric2 551 31.0%
trimeric3 329 18.5%
tetrameric4 95 5.4%
pentameric5 15 0.8%
hexameric6 10 0.6%
octameric8 6 0.3%
dodecameric12 5 0.3%

1,153 entries have the depositor's assembly corroborated by PISA, 566 carry the depositor's word alone and 56 were assigned by PISA where the depositor gave none. The middle figure is not a disagreement: PISA may have returned nothing or never run. 61 entries carry more than one assembly with different chain counts, so they have no single answer to quote: 1BML, 1GHY, 1IOD, 1KLI, 1L4D, 1L4Z, 1NL0, 1O0D, 1OPH, 1P2J, 1RJX, 1SG8, 1THS, 1TPA, 1X7A, 1XKB, 1XMN, 1YGC, 2A0Q, 2A2X.

Domain architecture

Every source's own domains on the seed axis, one row each. They are not merged: Pfam, CATH, SCOP and InterPro disagree about boundaries, and a merged track would state a consensus none of them gave.

CATHLamininHepatocyte Growth FactorTrypsin-like serine proteaSCOP2BEGF/Laminin-likeTrypsin-like serine proteaTrypsin-like serine proteaTrypsin-like serine proteaTrypsin-like serine proteaTrypsin-like serine proteaTrypsin-like serine proteaTrypsin-like serine protea1244488
DomainSourceSpan (seed)Chains
LamininCATH 2.10.25.10 87–178 98
Hepatocyte Growth FactorCATH 3.50.4.10 331–410 19
Trypsin-like serine proteasesCATH 2.40.10.10 337–444 3,709
EGF/Laminin-likeSCOP2B 8035338 127–177 81
Trypsin-like serine proteasesSCOP2B 8037496 235–457 526
Trypsin-like serine proteasesSCOP2B 8035341 235–467 131
Trypsin-like serine proteasesSCOP2B 8042154 235–488 109
Trypsin-like serine proteasesSCOP2B 8044201 235–471 105
Trypsin-like serine proteasesSCOP2B 8042216 235–479 76
Trypsin-like serine proteasesSCOP2B 8032586 235–477 19
Trypsin-like serine proteasesSCOP2B 8042267 237–483 22

What binds it

NAG NAG220 entries BEN BEN163 entries 0G6 0G640 entries FUC FUC37 entries BGC BGC24 entries 0GJ 0GJ15 entries AKG AKG14 entries GBS GBS12 entries MRZ MRZ12 entries ANH ANH11 entries ABN ABN10 entries 0Z6 0Z67 entries
ComponentClassNameEntriesBest (Å)
CAion Calcium Ion 888 0.75
SO4ion Sulfate Ion 566 0.75
GOLcryoprotectant Glycerol 318 0.75
NAion Sodium Ion 262 0.91
NAGcofactor 2-Acetamido-2-Deoxy-Beta-D-Glucopyranose 220 0.92
BENligand Benzamidine 163 0.75
CLion Chloride Ion 133 1.15
DMScryoprotectant Dimethyl Sulfoxide 125 0.95
EDOcryoprotectant 1,2-Ethanediol 102 0.91
PO4ion Phosphate Ion 67 1.12
MGion Magnesium Ion 53 1.37
ACTcryoprotectant Acetate Ion 50 0.93
0G6ligand D-Phenylalanyl-N-[(2s,3s)-6-{[Amino(Iminio)methyl]amino}-1-Chlor 40 1.30
CITbuffer Citric Acid 39 1.25
FUCcofactor Alpha-L-Fucopyranose 37 1.25
MNion Manganese (Ii) Ion 28 1.53
ZNion Zinc Ion 26 1.37
PEGcryoprotectant Di(Hydroxyethyl)ether 26 1.22
BGCligand Beta-D-Glucopyranose 24 1.47
MESbuffer 2-(N-Morpholino)-Ethanesulfonic Acid 20 0.97

How it crystallises

Parsed from the free text 1,436 depositors typed into _exptl_crystal_grow.pdbx_details, out of 1,517 entries that recorded anything at all. Median pH 7.3 (range 3.9 to 10.5).

Precipitants

PEG × Ammonium sulfate × Calcium chloride × Sodium chloride × Sodium citrate × Lithium sulfate × Isopropanol × Magnesium chloride × MPD × Sodium formate × PEG (unspecified) × Tacsimate × Ammonium phosphate × Sodium malonate ×

Buffers

Tris × HEPES × Citrate × MES × Sodium acetate × Phosphate × Imidazole × Bis-Tris × Sodium cacodylate × Bis-Tris propane × Succinate × CHES × ADA × CAPS ×

Which entries to trust

1,775 entries carry a wwPDB validation report: 992 clean, 459 worth a check and 324 with something to explain. Median clashscore 5.24, median RSRZ outliers 2.33%, median R-free minus R-work 0.035. 1,563 have released structure factors.

Across species

OrganismEntriesBest (Å)Ligand-boundSeed covered
Homo sapiens1,099 0.92 1099 100%
Bos taurus617 0.75 473 76%
Mus musculus15 1.33 10 55%
Salmo salar10 1.00 6 48%
synthetic construct8 1.54 8 8%
Rattus norvegicus5 1.60 3 48%
Sus scrofa3 1.90 5 77%
Streptomyces griseus4 1.05 2 48%
Oncorhynchus keta4 1.55 4 48%
Pontastacus leptodactylus2 1.20 0 47%
Pseudonaja textilis2 2.71 2 89%
Gadus morhua1 1.85 1 48%

Seed sequence

488 residues, numbered every ten. Every identity figure in this document is measured against this sequence.

active or binding site modified residue or glycosylation disulphide cysteine transmembrane or signal the 15 most-substituted positions

1MGRPLHLVLL SASLAGLLLL GESLFIRREQ ANNILARVTR ANSFLEEMKK GHLERECMEE
61TCSYEEAREV FEDSDKTNEF WNKYKDGDQC ETSPCQNQGK CKDGLGEYTC TCLEGFEGKN
121CELFTRKLCS LDNGDCDQFC HEEQNSVVCS CARGYTLADN GKACIPTGPY PCGKQTLERR
181KRSVAQATSS SGEAPDSITW KPYDAADLDP TENPFDLLDF NQTQPERGDN NLTRIVGGQE
241CKDGECPWQA LLINEENEGF CGGTILSEFY ILTAAHCLYQ AKRFKVRVGD RNTEQEEGGE
301AVHEVEVVIK HNRFTKETYD FDIAVLRLKT PITFRMNVAP ACLPERDWAE STLMTQKTGI
361VSGFGRTHEK GRQSTRLKML EVPYVDRNSC KLSSSFIITQ NMFCAGYDTK QEDACQGDSG
421GPHVTRFKDT YFVTGIVSWG EGCARKGKYG IYTKVTAFLK WIDRSMKTRG LPKAKSHAPE
481VITSSPLK

Sites are UniProt's curated features where the seed is a UniProt accession; the substituted positions are measured from this family's own alignment rather than annotated, and only the fifteen most substituted are marked: every position carrying a minority substitution would be most of the protein, because the family holds orthologues. A residue can carry more than one and is drawn with the first that applies, in the order of the key above.

Primary citations

One record per paper, not per entry.

YearCitation
2026 A 3.3- angstrom cryo-EM structure of an engineered high-affinity human prothrombinase complex. Blood doi:10.1182/blood.2025031527
2026 X-ray Diffraction Analyses of Trypsin Crystals Grown in the Presence of Additives Cryst.Growth Des. doi:10.1021/acs.cgd.5c01305
2026 N ‐Alkyl and N ‐Aryl Aminopyrazole Spirocarbamates: A Two-Pronged Lead Optimization Strategy to Identify Orally Bioavailable Plasma Kallikrein Inhibitors. Acs Med.Chem.Lett. doi:10.1021/acsmedchemlett.6c00066
2026 Structural basis of the promiscuity of the unusual Fe(II) and 2-oxoglutarate dependent human aspartate/asparagine-beta-hydroxylase. Nat Commun doi:10.1038/s41467-026-69425-w
2026 Prothrombinase processivity is conferred by substrate allostery. Embo J. doi:10.1038/s44318-026-00782-4
2026 TMPRSS2-mediated coronavirus spike activation and inhibition. Nat.Struct.Mol.Biol. doi:10.1038/s41594-026-01801-y
2026 Complete inhibition of beta-tryptase by tetramer dissociation and active site allostery due to a single antibody residue. Nat Commun doi:10.1038/s41467-026-70491-3
2026 Anticoagulation with mechanistically distinct FXI/FXIa antibodies amrecibart (REGN9933A2) and cenvacibart (REGN7508Cat). Blood doi:10.1182/blood.2025032276
2026 Structural insights into the exosite-mediated activation of factor IX by factor XIa using cryogenic electron microscopy. J.Thromb.Haemost. doi:10.1016/j.jtha.2026.08.015
2026 Structural requirements of blood factors binding to soluble hexon trimers with implications for adenovirus cell targeting and immune evasion. Plos Pathog. doi:10.1371/journal.ppat.1014389
2026 Molecular mechanism of cleavage at R271 during prothrombin activation revealed by cryo-EM. Blood doi:10.1182/blood.2025032364
2025 Large Library Docking and Biophysical Analysis of Small-Molecule TMPRSS2 Inhibitors. J.Med.Chem. doi:10.1021/acs.jmedchem.4c03089
2025 Structural and functional consequences of aspartate/asparagine-beta-hydroxylase variants causing Traboulsi Syndrome. J.Biol.Chem. doi:10.1016/j.jbc.2025.111008
2025 The crystal structure of coronavirus RBD-TMPRSS2 complex provides basis for the discovery of therapeutic antibodies. Nat Commun doi:10.1038/s41467-025-62023-2
2025 Integrating Surface Plasmon Resonance and Docking Analysis for Mechanistic Insights of Tryptase Inhibitors. Molecules doi:10.3390/molecules30061338
2025 The in vitro and crystallographic studies reveal the inhibitory potential of vitamin B 6 analogues against a serine protease trypsin. Int.J.Biol.Macromol. doi:10.1016/j.ijbiomac.2025.142433
2025 Discovery of BAY 3389934 Hydrochloride: A Potent and Selective Small-Molecule Dual Factor IIa/Xa Inhibitor with Short Half-Life for the Acute Treatment of Sepsis-Induced Coagulopathy. J.Med.Chem. doi:10.1021/acs.jmedchem.5c00538
2025 Replacement of a single residue changes the primary specificity of thrombin. J.Thromb.Haemost. doi:10.1016/j.jtha.2024.12.024
2025 Engineering ultrapotent trivalent anticoagulants through hybridisation of salivary peptides from multiple haematophagous organisms. Chem Sci doi:10.1039/d5sc04734j
2025 Molecular basis of vitamin K-dependent protein gamma-glutamyl carboxylation. Cell Res. doi:10.1038/s41422-025-01185-6
2025 Cryo-EM structure of coagulation factor Va bound to activated protein C. Blood doi:10.1182/blood.2025028476
2025 Blocking activation of the C1r zymogen defines a novel mode of complement inhibition. J.Biol.Chem. doi:10.1016/j.jbc.2025.108301
2025 Monoclonal antibodies against human TMPRSS2 prevent infection by any SARS-CoV-2 variant. Iscience doi:10.1016/j.isci.2025.113424
2025 Molecular basis of vitamin-K-driven gamma-carboxylation at the membrane interface. Nature doi:10.1038/s41586-025-08648-1
2025 Cryo-EM structure of the tissue factor/factor VIIa complex with a factor X mimetic reveals a novel allosteric mechanism. Blood doi:10.1182/blood.2025029430
2024 Alternative Linkage Chemistries in the Chemoenzymatic Synthesis of Microviridin-Based Cyclic Peptides. Org.Lett. doi:10.1021/acs.orglett.3c04045
2024 Water-medicated specifically targeting the S1 pockets among serine proteases using an arginine analogue. Bioorg.Chem. doi:10.1016/j.bioorg.2024.107734
2024 Structural basis of TMPRSS2 zymogen activation and recognition by the HKU1 seasonal coronavirus. Cell doi:10.1016/j.cell.2024.06.007
2024 An RNA aptamer exploits exosite-dependent allostery to achieve specific inhibition of coagulation factor IXa. Proc.Natl.Acad.Sci.USA doi:10.1073/pnas.2401136121
2024 Structural basis for the binding of famotidine, cimetidine, guanidine, and pimagedine with serine protease. Biochem.Biophys.Res.Commun. doi:10.1016/j.bbrc.2024.150603
2024 Kunitz-type trypsin inhibitor from durian (Durio zibethinus) employs a distinct loop for trypsin inhibition. Protein Sci. doi:10.1002/pro.5230
2024 Macrocyclic Inhibitors Targeting the Prime Site of the Fibrinolytic Serine Protease Plasmin. Chemmedchem doi:10.1002/cmdc.202400360
2024 Aptameric hirudins as selective and reversible EXosite-ACTive site (EXACT) inhibitors. Nat Commun doi:10.1038/s41467-024-48211-6
2024 Crystal structure of the Michaelis complex of trypsin with N-alpha-benzoyl-l-arginine ethyl ester J Chin Chem Soc doi:10.1002/jccs.202400214
2024 In vitro , in silico and crystallographic-based identification of serine protease inhibitors. Nat Prod Res doi:10.1080/14786419.2024.2425793
2024 Disulfi de constrained Fabs overcome target size limitation for high-resolution single-particle cryo-EM. Biorxiv doi:10.1101/2024.05.10.593593
2024 High-resolution crystal structure of human coronavirus HKU1 receptor binding domain bound to TMPRSS2 receptor Hlife doi:10.1016/j.hlife.2024.09.005
2024 Structural basis for the recognition of HCoV-HKU1 by human TMPRSS2. Cell Res. doi:10.1038/s41422-024-00958-9
2024 Human coronavirus HKU1 recognition of the TMPRSS2 host receptor. Cell doi:10.1016/j.cell.2024.06.006
2024 Molecular basis of TMPRSS2 recognition by Paeniclostridium sordellii hemorrhagic toxin. Nat Commun doi:10.1038/s41467-024-46394-6