Crystallization and preliminary X-ray crystallographic analysis of α-glucosidase HaG from Halomonas sp. strain H11.
The α-glucosidase HaG from the halophilic bacterium Halomonas sp. strain H11 catalyzes the hydrolysis of the glucosidic linkage at the nonreducing end of α-glucosides, such as maltose and sucrose, to release α-glucose. Based on its amino-acid sequence, this enzyme is classified as a member of glycoside hydrolase family 13. HaG has three unique characteristics: (i) a very narrow substrate specificity, almost exclusively hydrolyzing disaccharides; (ii) activation by monovalent cations, such as K(+), Rb(+), Cs(+) and NH4(+); and (iii) high transfer activity of the glucose moiety to the OH group of low-molecular-weight compounds, including glycerol and 6-gingerol. Crystallographic studies have been performed in order to understand these special features. An expression vector was constructed and recombinant HaG protein was overexpressed, purified and crystallized. A data set to 2.15 Å resolution was collected and processed. The crystal belonged to space group P212121, with unit-cell parameters a = 60.2, b = 119.2, c = 177.2 Å. The structure has been determined by molecular replacement using the isomaltulose synthase PalI as the search model (PDB entry 1m53).
School of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, People's Republic of China.
Xing
X
Shen
Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8689, Japan.
Wataru
W
Saburi
Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan.
Zuo-Qi
ZQ
Gai
Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan.
Keisuke
K
Komoda
Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan.
Jian
J
Yu
Nihon Shokuhin Kako Co. Ltd, Shizuoka 417-8530, Japan.
Teruyo
T
Ojima-Kato
Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8689, Japan.
Yusuke
Y
Kido
Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8689, Japan.
Hirokazu
H
Matsui
Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8689, Japan.
Haruhide
H
Mori
Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.
Min
M
Yao
D002414:Cations, Monovalent / Q000378:metabolism*; D003460:Crystallization / Q000379:methods*; D018360:Crystallography, X-Ray / Q000379:methods*; D020632:Halomonas / Q000201:enzymology*; D019751:Intramolecular Transferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D000520:alpha-Glucosidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D002414:Cations, Monovalent; D011994:Recombinant Proteins; D000520:alpha-Glucosidases; D019751:Intramolecular Transferases; C042002:isomaltulose synthase
HaG; Halomonas sp. strain H11