title: 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, α=β=γ=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%.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 210009, People's Republic of China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 210009, People's Republic of China.
authors.forename: Sha
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 210009, People's Republic of China.
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Liang
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 210009, People's Republic of China.
authors.forename: Xiaohai
authors.initials: X
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 210009, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000737:chemistry* / Q000302:isolation & purification; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification; D003460:Crystallization; D018360:Crystallography, X-Ray; D052197:Limosilactobacillus fermentum / Q000201:enzymology*; D008969:Molecular Sequence Data
chemical_list: D001426:Bacterial Proteins; D019747:Aldose-Ketose Isomerases; C019715:L-arabinose isomerase
keywords: d-tagatose; l-arabinose isomerase; rare sugars; synchrotron radiation