Download MendeleyThe 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, B.F., Stone, S.R., Esmon, C.T., Stubbs, M.T.(1997) EMBO J 16: 2977-2984
- PubMed: 9214615
- DOI: https://doi.org/10.1093/emboj/16.11.2977
- Primary Citation of Related Structures:
1BTH - PubMed Abstract:
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.
Organizational Affiliation:
Max-Planck-Institut für Biochemie, Abteilung Strukturforschung, Martinsried, Germany.
