Purification, crystallization, and preliminary X-ray diffraction analysis of an S-formylglutathione hydrolase (VaSFGH) homolog from Variovorax sp. PAMC 28711

Abstract

S-formylglutathione hydrolase (SFGH) is an esterase that hydrolyzes S-formylglutathione into formic acid and glutathione. As SFGHs are also able to hydrolyze thioesters as well as non-thioester substrates, they have attracted considerable attention as potential biocatalysts. Although the substrate specificity of various SFGHs has been determined, the detailed structural differences relating to substrate preference remain unclear. Here, we present overexpression, purification, and preliminary X-ray crystallographic data for an SFGH from Variovorax sp. PAMC 28711 (VaSFGH). The VaSFGH protein was over-expressed in Escherichia coli and successfully crystallized in 0.2 M sodium chloride, 0.1 M Bis-Tris:HCl (pH 6.5), and 20 % (w/v) PEG 3350. A complete native X-ray diffraction dataset was collected up to 2.38 A resolution and processed in the C2 space group with unit-cell parameters a = 53.2 A, b = 76.4 A, c = 199.9 A, α = 90 °, β = 90.2 °, and γ = 90 °. Moreover, VaSFGH exhibited higher esterase activity toward shorter-chain esters. Based on its structural determination, future studies will elucidate the substrate-binding mechanism and specificity of VaSFGH at the molecular level.