PDBsum entry 1v4l

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protein Protein-protein interface(s) links
Blood clotting PDB id
Protein chains
135 a.a. *
125 a.a. *
Waters ×536
* Residue conservation analysis
PDB id:
Name: Blood clotting
Title: Crystal structure of a platelet agglutination factor isolate venom of taiwan habu (trimeresurus mucrosquamatus)
Structure: Mucrocetin alpha chain. Chain: a, c, e. Mucrocetin beta chain. Chain: b, d, f
Source: Protobothrops mucrosquamatus. Organism_taxid: 103944. Secretion: snake venom. Secretion: snake venom
Biol. unit: 60mer (from PDB file)
2.80Å     R-factor:   0.235     R-free:   0.298
Authors: K.-F.Huang,T.-P.Ko,A.H.-J.Wang
Key ref: K.F.Huang et al. (2004). Crystal structure of a platelet-agglutinating factor isolated from the venom of Taiwan habu (Trimeresurus mucrosquamatus). Biochem J, 378, 399-407. PubMed id: 14613481 DOI: 10.1042/BJ20031507
14-Nov-03     Release date:   02-Dec-03    
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Protein chains
Pfam   ArchSchema ?
Q6TPH0  (MUCA_PROMU) -  Snaclec mucrocetin subunit alpha
158 a.a.
135 a.a.
Protein chains
Pfam   ArchSchema ?
Q6TPG9  (MUCB_PROMU) -  Snaclec mucrocetin subunit beta
148 a.a.
125 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 1 residue position (black cross)

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     extracellular region   1 term 
  Biochemical function     carbohydrate binding     1 term  


DOI no: 10.1042/BJ20031507 Biochem J 378:399-407 (2004)
PubMed id: 14613481  
Crystal structure of a platelet-agglutinating factor isolated from the venom of Taiwan habu (Trimeresurus mucrosquamatus).
K.F.Huang, T.P.Ko, C.C.Hung, J.Chu, A.H.Wang, S.H.Chiou.
Platelet glycoprotein Ib (GPIb)-binding proteins (GPIb-BPs) from snake venoms are usually C-type lectins, which target specific sites of GPIbalpha and elicit distinct effects on platelets. In the present paper, we report a tetrameric platelet-agglutinating factor (molecular mass 121.1 kDa), termed mucrocetin, purified from the venom of Taiwan habu (Trimeresurus mucrosquamatus ). Mucrocetin is a GPIbalpha agonist with a binding site distinct from that of flavocetin-A (a snake venom GPIbalpha antagonist) on GPIbalpha, in spite of the high sequence identity (94.6%) between the two venom lectins. The crystal structure of mucrocetin was solved and refined to 2.8 A (1 A=0.1 nm) resolution, which shows an interesting crystal packing of six-layer cylinders of doughnut-shaped molecules. The four alphabeta heterodimers are arranged in an unusual square-shaped ring stabilized by four interdimer 'head-to-tail' disulphide bridges. Detailed structural comparison between mucrocetin and flavocetin-A suggests that their disparate platelet effects are probably attributable to different charge distributions on the putative concave binding surface. A unique positively charged patch on the binding surface of mucrocetin, formed by Lys102, Lys108, Lys109 and Arg123 in the alpha-subunit coupled with Lys22, Lys102, Lys116 and Arg117 in the beta-subunit, appears to be the primary determinant of its platelet-agglutinating activity. Conceivably, this interesting venom factor may provide a useful tool to study platelet agglutination by binding to the GPIb-IX-V complex.

Literature references that cite this PDB file's key reference

  PubMed id Reference
21277886 T.Sajevic, A.Leonardi, and I.Kri┼żaj (2011).
Haemostatically active proteins in snake venoms.
  Toxicon, 57, 627-645.  
21256857 Z.Chen, J.Wu, Y.Zhang, X.Yang, G.Yu, S.Zhu, W.Lee, Q.Lu, and Y.Zhang (2011).
A novel platelet glycoprotein Ib-binding protein with human platelet aggregation-inhibiting activity from Trimeresurus jerdonii venom.
  Toxicon, 57, 672-679.  
16206329 A.Bazaa, N.Marrakchi, M.El Ayeb, L.Sanz, and J.J.Calvete (2005).
Snake venomics: comparative analysis of the venom proteomes of the Tunisian snakes Cerastes cerastes, Cerastes vipera and Macrovipera lebetina.
  Proteomics, 5, 4223-4235.  
  16508096 G.Xu, Q.Huang, M.Teng, P.Liu, Y.Dong, and L.Niu (2005).
Crystallization and preliminary X-ray crystallographic analysis of agkicetin-C from Deinagkistrodon acutus venom.
  Acta Crystallogr Sect F Struct Biol Cryst Commun, 61, 75-78.  
15502319 G.Xu, M.Teng, L.Niu, P.Liu, Y.Dong, Q.Liu, Q.Huang, and Q.Hao (2004).
Purification, characterization, crystallization and preliminary X-ray crystallographic analysis of two novel C-type lectin-like proteins: Aall-A and Aall-B from Deinagkistrodon acutus venom.
  Acta Crystallogr D Biol Crystallogr, 60, 2035-2037.  
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