α₁-Antichymotrypsin inactivates staphylococcal cysteine protease in cross-class inhibition

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• 作者：Benedykt Wladyka^a ; ^{wladykab@interia.pl} ; Agata J. Kozik^a ; ^{agata.kozik@poczta.onet.pl} ; Michal Bukowski^a ; ^{mbukow@gmail.com} ; Anna Rojowska^a ; ^{gatita@interia.pl} ; Tomasz Kantyka^b ; ^{tkantyka@gmail.com} ; Grzegorz Dubin^b ; ^{grzegorz.dubin@uj.edu.pl} ; Adam Dubin^a ; ^{adam.dubin@uj.edu.pl}
• 关键词：Cross-class inhibition ; Protease inhibitor ; Serpin ; SERPINA3 ; Staphopain ; Staphylococcus
• 刊名：Biochimie
• 出版年：2011
• 出版时间：May 2011
• 年：2011
• 卷：93
• 期：5
• 页码：948-953
• 全文大小：424 K

文摘

Staphylococcal cysteine proteases are implicated as virulence factors in human and avian infections. Human strains of Staphylococcus aureus secrete two cysteine proteases (staphopains A and B), whereas avian strains express staphopain C (ScpA2), which is distinct from both human homologues. Here, we describe probable reasons why the horizontal transfer of a plasmid encoding staphopain C between avian and human strains has never been observed. The human plasma serine protease inhibitor α₁-antichymotrypsin (ACHT) inhibits ScpA2. Together with the lack of ScpA2 inhibition by chicken plasma, these data may explain the exclusively avian occurrence of ScpA2. We also clarify the mechanistic details of this unusual cross-class inhibition. Analysis of mutated ACHT variants revealed that the cleavage of the Leu383-Ser384 peptide bond results in ScpA2 inhibition, whereas hydrolysis of the preceding peptide bond leads to ACHT inactivation. This evidence is consistent with the suicide-substrate-like mechanism of inhibition.