Galactaro 未-Lactone Isomerase: Lactone Isomerization by a Member of the Amidohydrolase Superfamily

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• 作者：Jason T. Bouvier ; Fiona P. Groninger-Poe ; Matthew Vetting ; Steven C. Almo ; John A. Gerlt
• 刊名：Biochemistry
• 出版年：2014
• 出版时间：February 4, 2014
• 年：2014
• 卷：53
• 期：4
• 页码：614-616
• 全文大小：255K
• ISSN：1520-4995

文摘

Agrobacterium tumefaciens strain C58 can utilize an class="smallcaps">dan>-galacturonate as a sole source of carbon via a pathway in which the first step is oxidation of an class="smallcaps">dan>-galacturonate to an class="smallcaps">dan>-galactaro-1,5-lactone. We have identified a novel enzyme, an class="smallcaps">dan>-galactarolactone isomerase (GLI), that catalyzes the isomerizaton of an class="smallcaps">dan>-galactaro-1,5-lactone to an class="smallcaps">dan>-galactaro-1,4-lactone. GLI, a member of the functionally diverse amidohydrolase superfamily, is a homologue of LigI that catalyzes the hydrolysis of 2-pyrone-4,6-dicarboxylate in lignin degradation. The ability of GLI to catalyze lactone isomerization instead of hydrolysis can be explained by the absence of the general basic catalysis used by 2-pyrone-4,6-dicarboxylate lactonase.