Acta Crystallographica Section D

Biological Crystallography

Volume 60, Part 7 (July 2004)

research papers

Acta Cryst. (2004). D60, 1237-1243 [ doi:10.1107/S0907444904010522 ]

Structure of an aryl esterase from Pseudomonas fluorescens

J. D. Cheeseman, A. Tocilj, S. Park, J. D. Schrag and R. J. Kazlauskas

Abstract: The structure of PFE, an aryl esterase from Pseudomonas fluorescens, has been solved to a resolution of 1.8 Å 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 atoms between PFE and its five closest structural neighbors averaging 0.8 Å. PFE has far less similarity (r.m.s. deviation in 218 C atoms of 5.0 Å) 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.

PDB reference: 1va4

Keywords: Pseudomonas fluorescens esterases; /-hydrolases; non-heme haloperoxidases.