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2aip

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Crystal structure of native protein C activator from the venom of copperhead snake Agkistrodon contortrix contortrix

Structural highlights

2aip is a 1 chain structure with sequence from Agkistrodon contortrix contortrix. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.65Å
Ligands:	, , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

VSPCA_AGKCO Snake venom serine protease that selectively cleaves the heavy chain of protein C (PROC). This activation is thrombomodulin-independent.^[1]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Protein C activation initiated by the thrombin-thrombomodulin complex forms the major physiological anticoagulant pathway. Agkistrodon contortrix contortrix protein C activator, a glycosylated single-chain serine proteinase, activates protein C without relying on thrombomodulin. The crystal structures of native and inhibited Agkistrodon contortrix contortrix protein C activator determined at 1.65 and 1.54 A resolutions, respectively, indicate the pivotal roles played by the positively charged belt and the strategic positioning of the three carbohydrate moieties surrounding the catalytic site in protein C recognition, binding, and activation. Structural changes in the benzamidine-inhibited enzyme suggest a probable function in allosteric regulation for the anion-binding site located in the C-terminal extension, which is fully conserved in snake venom serine proteinases, that preferentially binds Cl(1-) instead of SO(4)(2-).

Thrombomodulin-independent activation of protein C and specificity of hemostatically active snake venom serine proteinases: crystal structures of native and inhibited Agkistrodon contortrix contortrix protein C activator.,Murakami MT, Arni RK J Biol Chem. 2005 Nov 25;280(47):39309-15. Epub 2005 Sep 14. PMID:16162508^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Kisiel W, Kondo S, Smith KJ, McMullen BA, Smith LF. Characterization of a protein C activator from Agkistrodon contortrix contortrix venom. J Biol Chem. 1987 Sep 15;262(26):12607-13. PMID:3624272
↑ Murakami MT, Arni RK. Thrombomodulin-independent activation of protein C and specificity of hemostatically active snake venom serine proteinases: crystal structures of native and inhibited Agkistrodon contortrix contortrix protein C activator. J Biol Chem. 2005 Nov 25;280(47):39309-15. Epub 2005 Sep 14. PMID:16162508 doi:10.1074/jbc.M508502200