The Na+ binding site of thrombin.
Research article published in The Journal of biological chemistry (1995)
Abstract
Thrombin is an allosteric serine protease existing in two forms, slow and fast, targeted toward anticoagulant and procoagulant activities. The slow --> fast transition is induced by Na+ binding to a site contained within a cylindrical cavity formed by three antiparallel beta-strands of the B-chain (Met180-Tyr184a, Lys224-Tyr228, and Val213-Gly219) diagonally crossed by the Glu188-Glu192 strand. The site is shaped further by the loop connecting the last two beta-strands and is located more than 15 A away from the catalytic triad. The cavity traverses through thrombin from the active site to the opposite surface and contains Asp189 of the primary specificity site near its midpoint. The bound Na+ is coordinated octahedrally by the carbonyl oxygen atoms of Tyr184a, Arg221a, and Lys224, and by three highly conserved water molecules in the D-Phe-Pro-Arg chloromethylketone thrombin. The sequence in the Na+ binding loop is highly conserved in thrombin from 11 different species and is homologous to that found in other serine proteases involved in blood coagulation. Mutation of two Asp residues flanking Arg221a (D221A/D222K) almost abolishes the allosteric properties of thrombin and shows that the Na+ binding loop is also involved in direct recognition of protein C and antithrombin.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Zusammenfassung
Thrombin is an allosteric serine protease existing in two forms, slow and fast, targeted toward anticoagulant and procoagulant activities. The slow --> fast transition is induced by Na+ binding to a site contained within a cylindrical cavity formed by three antiparallel beta-strands of the B-chain...
Warum dies für die Hirudotherapie relevant ist
Das Abstract charakterisiert die strukturelle Grundlage der Na+-Bindungsstelle von Thrombin, identifiziert die Beta-Strang-Tasche, die beteiligten Reste und Wassermoleküle der oktaedrischen Na+-Koordination und berichtet, dass D221A/D222K-Mutationen in der Nähe der Na+-Bindungsschleife die allosterischen Eigenschaften von Thrombin nahezu vollständig aufheben und die Erkennung von Protein C und Antithrombin beeinträchtigen. Diese Arbeit betrifft die Thrombin-Allosterie und die Spezifität von Blutgerinnungsproteasen. Das Abstract erwähnt jedoch weder Blutegel, Hirudin, Hirudotherapie noch eine vom Blutegel stammende Verbindung, sodass es keine direkte Evidenz liefert, die für das ASH-Domänenfeld relevant ist. Seine Relevanz beschränkt sich auf die allgemeine strukturelle Biologie von Thrombin, nicht auf Blutegel-basierte oder von Blutegeln stammende Therapeutika.
Zitation
Verwandter klinischer Kontext
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