Computational, Structural, and Kinetic Evidence That Vibrio vulnificus FrsA Is Not a Cofactor-Independent Pyruvate Decarboxylase

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• 作者：Whitney F. Kellett ; Elizabeth Brunk ; Bijoy J. Desai ; Alexander A. Fedorov ; Steven C. Almo ; John A. Gerlt ; Ursula Rothlisberger ; Nigel G. J. Richards
• 刊名：Biochemistry
• 出版年：2013
• 出版时间：March 19, 2013
• 年：2013
• 卷：52
• 期：11
• 页码：1842-1844
• 全文大小：205K
• 年卷期：v.52,no.11(March 19, 2013)
• ISSN：1520-4995

文摘

The fermentation鈥搑espiration switch (FrsA) protein in Vibrio vulnificus was recently reported to catalyze the cofactor-independent decarboxylation of pyruvate. We now report quantum mechanical/molecular mechenical calculations that examine the energetics of C鈥揅 bond cleavage for a pyruvate molecule bound within the putative active site of FrsA. These calculations suggest that the barrier to C鈥揅 bond cleavage in the bound substrate is 28 kcal/mol, which is similar to that estimated for the uncatalyzed decarboxylation of pyruvate in water at 25 掳C. In agreement with the theoretical predictions, no pyruvate decarboxylase activity was detected for recombinant FrsA protein that could be crystallized and structurally characterized. These results suggest that the functional annotation of FrsA as a cofactor-independent pyruvate decarboxylase is incorrect.