1sr5 | pdb_00001sr5
| |||||||||||||
| 1sr5, resolution 3.10Å | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ligands: | NAG, NT1, NT2 | ||||||||||||
| Activity: | Thrombin, with EC number 3.4.21.5 | ||||||||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
ANTITHROMBIN-ANHYDROTHROMBIN-HEPARIN TERNARY COMPLEX STRUCTURE
Overview
Antithrombin, the principal physiological inhibitor of the blood coagulation proteinase thrombin, requires heparin as a cofactor. We report the crystal structure of the rate-determining encounter complex formed between antithrombin, anhydrothrombin and an optimal synthetic 16-mer oligosaccharide. The antithrombin reactive center loop projects from the serpin body and adopts a canonical conformation that makes extensive backbone and side chain contacts from P5 to P6' with thrombin's restrictive specificity pockets, including residues in the 60-loop. These contacts rationalize many earlier mutagenesis studies on thrombin specificity. The 16-mer oligosaccharide is just long enough to form the predicted bridge between the high-affinity pentasaccharide-binding site on antithrombin and the highly basic exosite 2 on thrombin, validating the design strategy for this synthetic heparin. The protein-protein and protein-oligosaccharide interactions together explain the basis for heparin activation of antithrombin as a thrombin inhibitor.
About this Structure
1SR5 is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
The ternary complex of antithrombin-anhydrothrombin-heparin reveals the basis of inhibitor specificity., Dementiev A, Petitou M, Herbert JM, Gettins PG, Nat Struct Mol Biol. 2004 Sep;11(9):863-7. Epub 2004 Aug 15. PMID:15311268
Page seeded by OCA on Sun Mar 30 23:45:56 2008
