Cheeseman Jeremy D, Tocilj Ante, Park Seongsoon, Schrag Joseph D, Kazlauskas Romas J
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreál, Québec H3A 2K6, Canada.
Acta Crystallogr D Biol Crystallogr. 2004 Jul;60(Pt 7):1237-43. doi: 10.1107/S0907444904010522. Epub 2004 Jun 22.
The structure of PFE, an aryl esterase from Pseudomonas fluorescens, has been solved to a resolution of 1.8 A by X-ray diffraction and shows a characteristic alpha/beta-hydrolase fold. In addition to catalyzing the hydrolysis of esters in vitro, PFE also shows low bromoperoxidase activity. PFE shows highest structural similarity, including the active-site environment, to a family of non-heme bacterial haloperoxidases, with an r.m.s. deviation in 271 C(alpha) atoms between PFE and its five closest structural neighbors averaging 0.8 A. PFE has far less similarity (r.m.s. deviation in 218 C(alpha) atoms of 5.0 A) to P. fluorescens carboxyl esterase. PFE favors activated esters with small acyl groups, such as phenyl acetate. The X-ray structure of PFE reveals a significantly occluded active site. In addition, several residues, including Trp28 and Met95, limit the size of the acyl-binding pocket, explaining its preference for small acyl groups.
荧光假单胞菌的芳基酯酶PFE的结构已通过X射线衍射解析至1.8 Å的分辨率，显示出典型的α/β-水解酶折叠结构。除了在体外催化酯的水解外，PFE还表现出较低的溴过氧化物酶活性。PFE与一类非血红素细菌卤过氧化物酶在结构上具有最高的相似性，包括活性位点环境，PFE与其五个最接近的结构邻居之间的271个Cα原子的均方根偏差平均为0.8 Å。PFE与荧光假单胞菌羧酸酯酶的相似性要低得多（218个Cα原子的均方根偏差为5.0 Å）。PFE倾向于具有小酰基的活化酯，如苯乙酸酯。PFE的X射线结构显示出一个明显封闭的活性位点。此外，包括Trp28和Met95在内的几个残基限制了酰基结合口袋的大小，这解释了它对小酰基的偏好。
