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Crystallization and preliminary X‐ray crystallographic analysis of L‐arabinose isomerase from thermophilic Geobacillus kaustophilus
Author(s) -
Cao ThinhPhat,
Choi Jin Myung,
Lee SangJae,
Lee YongJik,
Lee SungKeun,
Jun Youngsoo,
Lee DongWoo,
Lee Sung Haeng
Publication year - 2014
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x13033724
Subject(s) - thermophile , geobacillus stearothermophilus , isomerase , monoclinic crystal system , chemistry , arabinose , crystallography , crystallization , crystal structure , stereochemistry , biochemistry , fermentation , organic chemistry , enzyme , xylose
L‐Arabinose isomerase (AI), which catalyzes the isomerization of L‐arabinose to L‐ribulose, can also convert D‐galactose to D‐tagatose, a natural sugar replacer, which is of commercial interest in the food and healthcare industries. Intriguingly, mesophilic and thermophilic AIs showed different substrate preferences and metal requirements in catalysis and different thermostabilities. However, the catalytic mechanism of thermophilic AIs still remains unclear. Therefore, thermophilic Geobacillus kaustophilus AI (GKAI) was overexpressed, purified and crystallized, and a preliminary X‐ray diffraction data set was obtained. Diffraction data were collected from a GKAI crystal to 2.70 Å resolution. The crystal belonged to the monoclinic space group C 2, with unit‐cell parameters a = 224.12, b = 152.95, c = 91.28 Å, β = 103.61°. The asymmetric unit contained six molecules, with a calculated Matthews coefficient of 2.25 Å 3 Da −1 and a solvent content of 45.39%. The three‐dimensional structure determination of GKAI is currently in progress by molecular replacement and model building.