Crystallization and diffraction analysis of Sm23: an SGNH-family arylesterase from Sinorhizobium meliloti 1021.

Industrial demand for active biocatalysts with desirable biochemical properties is constantly increasing and the discovery and characterization of novel esterases is potentially useful for industrial processes. Here, X-ray crystallographic studies of an (R)-specific SGNH arylesterase (Sm23) from Sinorhizobium meliloti 1021 are reported. The recombinant protein was expressed in Escherichia coli with a His tag and purified to homogeneity. Sm23 was crystallized using 0.2 M magnesium formate as a precipitant and X-ray diffraction data were collected to a resolution of 2.2 Å with an R(merge) of 6.9%. The crystals of SM23 belonged to the I-centred tetragonal space group I4(1)22, with unit-cell parameters a = b = 126.6, c = 190.9 Å. A molecular-replacement solution was obtained using the crystal structure of arylesterase from Mycobacterium smegmatis as a template.