Functional annotation and kinetic characterization of PhnO from Salmonella enterica
Functional annotation and kinetic characterization of PhnO from Salmonella enterica
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DOI：
10.1021/bi052297p
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发表时间：
2006-03-07
期刊：
影响因子：
2.9
通讯作者：
Blanchard, JS
中科院分区：
文献类型：
--
作者：
Errey, JC;Blanchard, JS
磷是所有生物体的必需营养素。在无机磷酸盐饥饿的条件下，来自Pho调节子的基因被诱导，允许微生物使用膦酸盐作为磷的来源。由于与GCN 5相关的N-酰基转移酶家族（GNAT）成员的序列同源性，phnO基因先前被注释为未知功能的转录调节因子。PhnO现在可以在功能上注释为氨基烷基膦酸N-乙酰转移酶，其能够乙酰化一系列氨基烷基膦酸。研究表明，PhnO收益通过一个有序的，顺序的动力学机制与AcCoA结合，其次是氨基烷基膦酸酯。胺对AcCoA的硫酯的攻击产生四面体中间体，该四面体中间体塌陷以产生产物。该酶还需要二价金属离子才能活性，这是GNAT家族成员这种要求的第一个例子。
Phosphorus is an essential nutrient for all living organisms. Under conditions of inorganic phosphate starvation, genes from the Pho regulon are induced, allowing microorganisms to use phosphonates as a source of phosphorus. The phnO gene was previously annotated as a transcriptional regulator of unknown 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-acetyltransferase which is able to acetylate a range of aminoalkylphosphonic acids. Studies revealed that PhnO proceeds via 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 to generate the products. The enzyme also requires a divalent metal ion for activity, which is the first example of this requirement for a GNAT family member.