Interactions outside the proteinase-binding loop contribute significantly to the inhibition of activated coagulation factor XII by its canonical inhibitor from corn

Korneeva, V.A.; Trubetskov, M.M.; Korshunova, A.V.; Lushchekina, S.V.; Kolyadko, V.N.; Sergienko, O.V.; Lunin, V.G.; Panteleev, M.A.; Ataullakhanov, F.I.

Авторы: Korneeva V.A., Trubetskov M.M., Korshunova A.V., Lushchekina S.V., Kolyadko V.N., Sergienko O.V., Lunin V.G., Panteleev M.A., Ataullakhanov F.I.
Журнал: Journal of Biological Chemistry
Том: 289
Номер: 20
Год издания: 2014
Издательство: American Society for Biochemistry and Molecular Biology Inc.
Местоположение издательства: United States
Первая страница: 14109
Последняя страница: 14120
DOI: 10.1074/jbc.M114.553735
Аннотация: Activated factor XII (FXIIa) is selectively inhibited by corn Hageman factor inhibitor (CHFI) among other plasma proteases. CHFI is considered a canonical serine protease inhibitor that interacts with FXIIa through its protease-binding loop. Here we examined whether the protease-binding loop alone is sufficient for the selective inhibition of serine proteases or whether other regions of a canonical inhibitor are involved. Six CHFI mutants lacking different N- and C-terminal portions were generated. CHFI-234, which lacks the first and fifth disulfide bonds and 11 and 19 amino acid residues at the N and C termini, respectively, exhibited no significant changes in FXIIa inhibition (Ki = 3.2 +/- 0.4 nm). CHFI-123, which lacks 34 amino acid residues at the C terminus and the fourth and fifth disulfide bridges, inhibited FXIIa with a Ki of 116 +/- 16 nm. To exclude interactions outside the FXIIa active site, a synthetic cyclic peptide was tested. The peptide contained residues 20-45 (Protein Data Bank code 1BEA), and a C29D substitution was included to avoid unwanted disulfide bond formation between unpaired cysteines. Surprisingly, the isolated protease-binding loop failed to inhibit FXIIa but retained partial inhibition of trypsin (Ki = 11.7 +/- 1.2 mum) and activated factor XI (Ki = 94 +/- 11 mum). Full-length CHFI inhibited trypsin with a Ki of 1.3 +/- 0.2 nm and activated factor XI with a Ki of 5.4 +/- 0.2 mum. Our results suggest that the protease-binding loop is not sufficient for the interaction between FXIIa and CHFI; other regions of the inhibitor also contribute to specific inhibition
Добавил в систему: Атауллаханов Фазоил Иноятович

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Interactions outside the proteinase-binding loop contribute significantly to the inhibition of activated coagulation factor XII by its canonical inhibitor from cornстатья