1bth
From Proteopedia
STRUCTURE OF THROMBIN COMPLEXED WITH BOVINE PANCREATIC TRYPSIN INHIBITOR
Overview
Previous crystal structures of thrombin indicate that the 60-insertion loop is a rigid moiety that partially occludes the active site, suggesting that this structural feature plays a decisive role in restricting thrombin's specificity. This restricted specificity is typified by the experimental observation that thrombin is not inhibited by micromolar concentrations of basic pancreatic trypsin inhibitor (BPTI). Surprisingly, a single atom mutation in thrombin (E192Q) results in a 10(-8) M affinity for BPTI. The crystal structure of human thrombin mutant E192Q has been solved in complex with BPTI at 2.3 A resolution. Binding of the Kunitz inhibitor is accompanied by gross structural rearrangements in thrombin. In particular, thrombin's 60-loop is found in a significantly different conformation. Concomitant reorganization of other surface loops that surround the active site, i.e. the 37-loop, the 148-loop and the 99-loop, is observed. Thrombin can therefore undergo major structural reorganization upon strong ligand binding. Implications for the interaction of thrombin with antithrombin and thrombomodulin are discussed.
About this Structure
1BTH is a Protein complex structure of sequences from Bos taurus. Full crystallographic information is available from OCA.
Reference
The thrombin E192Q-BPTI complex reveals gross structural rearrangements: implications for the interaction with antithrombin and thrombomodulin., van de Locht A, Bode W, Huber R, Le Bonniec BF, Stone SR, Esmon CT, Stubbs MT, EMBO J. 1997 Jun 2;16(11):2977-84. PMID:9214615 Page seeded by OCA on Fri May 2 11:56:11 2008
