An efficient, multiply promiscuous hydrolase in the alkaline phosphatase superfamily
An efficient, multiply promiscuous hydrolase in the alkaline phosphatase superfamily
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DOI：
10.1073/pnas.0903951107
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发表时间：
2010-01
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影响因子：
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通讯作者：
B. van Loo;S. Jonas;A. Babtie;A. Benjdia;O. Berteau;M. Hyvönen;F. Hollfelder
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作者：
B. van Loo;S. Jonas;A. Babtie;A. Benjdia;O. Berteau;M. Hyvönen;F. Hollfelder
我们报告了一种催化混杂的酶，能够有效促进六种不同底物类别的水解。这种酶最初被指定为膦酸单酯水解酶（PMH），对于磷酸单酯、二酯和三酯、膦酸单酯、硫酸单酯和磺酸单酯的水解，该酶表现出实质性的二级速率加速（（kcat/KM）/kw），范围从107到高达1019。该底物集合包括在0和-2之间的底物电荷范围、不同性质的过渡态，并且涉及在两个不同反应中心（P和S）的攻击。在接近中性的情况下，固有反应性（半衰期）从200天到105年不等。一组相对困难的反应的显著速率加速表明，有效的催化不一定限于仅一个过渡态的有效稳定。PMH的晶体结构将其鉴定为碱性磷酸酶超家族的成员。PMH包括四个以前在这个超家族中观察到的天然活性，并通过两个进一步的活性扩展其库，其中之一是磺酸单酯酶，以前没有观察到天然酶。因此，PMH是迄今为止描述的最混杂的水解酶之一。超家族活动之间的功能联系可以被推测为通过基因复制在功能进化中发挥了作用。
We report a catalytically promiscuous enzyme able to efficiently promote the hydrolysis of six different substrate classes. Originally assigned as a phosphonate monoester hydrolase (PMH) this enzyme exhibits substantial second-order rate accelerations ((kcat/KM)/kw), ranging from 107 to as high as 1019, for the hydrolyses of phosphate mono-, di-, and triesters, phosphonate monoesters, sulfate monoesters, and sulfonate monoesters. This substrate collection encompasses a range of substrate charges between 0 and -2, transition states of a different nature, and involves attack at two different reaction centers (P and S). Intrinsic reactivities (half-lives) range from 200 days to 105 years under near neutrality. The substantial rate accelerations for a set of relatively difficult reactions suggest that efficient catalysis is not necessarily limited to efficient stabilization of just one transition state. The crystal structure of PMH identifies it as a member of the alkaline phosphatase superfamily. PMH encompasses four of the native activities previously observed in this superfamily and extends its repertoire by two further activities, one of which, sulfonate monoesterase, has not been observed previously for a natural enzyme. PMH is thus one of the most promiscuous hydrolases described to date. The functional links between superfamily activities can be presumed to have played a role in functional evolution by gene duplication.