Functional Annotation and Kinetic Characterization of PhnO from Salmonella enterica

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• 作者：James C. Errey and John S. Blanchard
• 刊名：Biochemistry
• 出版年：2006
• 出版时间：March 7, 2006
• 年：2006
• 卷：45
• 期：9
• 页码：3033 - 3039
• 全文大小：106K
• 年卷期：v.45,no.9(March 7, 2006)
• ISSN：1520-4995

文摘

Phosphorus is an essential nutrient for all living organisms. Under conditions of inorganicphosphate starvation, genes from the Pho regulon are induced, allowing microorganisms to use phosphonatesas a source of phosphorus. The phnO gene was previously annotated as a transcriptional regulator ofunknown function due to sequence homology with members of the GCN5-related N-acyltransferase family(GNAT). PhnO can now be functionally annotated as an aminoalkylphosphonic acid N-acetyltransferasewhich is able to acetylate a range of aminoalkylphosphonic acids. Studies revealed that PhnO proceedsvia an ordered, sequential kinetic mechanism with AcCoA binding first followed by aminoalkylphosphonate.Attack by the amine on the thioester of AcCoA generates the tetrahedral intermediate that collapses togenerate the products. The enzyme also requires a divalent metal ion for activity, which is the first exampleof this requirement for a GNAT family member.