Protein purification, crystallization and preliminary X-ray diffraction analysis of L-arabinose isomerase from Lactobacillus fermentum CGMCC2921.

ABSTRACT: L-Arabinose isomerase (AI) catalyzes the isomerization of L-arabinose to L-ribulose, as well as that of D-galactose to D-tagatose. A thermophilic AI derived from Lactobacillus fermentum CGMCC2921 (LFAI) was overexpressed in Escherichia coli BL21 (DE3). This enzyme was purified to over 95% purity by nickel affinity, Mono-Q ion-exchange and size-exclusion chromatography. The LFAI protein was crystallized from either 0.1?M bis-tris pH 6.5, 23% PEG 3350, 0.3?M NaCl (form 1 crystals) or 0.1?M bis-tris pH 6.0, 25% PEG monomethyl ether 5000 (form 2 crystals). Diffraction data from form 1 LFAI crystals were collected to 2.80?Å resolution using synchrotron radiation. The form 1 crystals belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a=85.11, b=184.57, c=186.26?Å, ?=?=?=90°. The asymmetric unit contained six LFAI subunits, corresponding to a calculated Matthews coefficient of 2.29?Å3?Da(-1) and a solvent content of 46.22%.

SUBMITTER: Xu Z 

PROVIDER: S-EPMC4304743 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature