title: A new α-galactosidase from thermoacidophilic Alicyclobacillus sp. A4 with wide acceptor specificity for transglycosylation.
abstract: An α-galactosidase gene (gal36A4) of glycosyl hydrolase family 36 was identified in the genome of Alicyclobacillus sp. A4. It contains an ORF of 2,187 bp and encodes a polypeptide of 728 amino acids with a calculated molecular mass of 82.6 kDa. Deduced Gal36A4 shows the typical GH36 organization of three domains--the N-terminal β-sheets, the catalytic (β/α)8-barrels, and the C-terminal antiparallel β-sheet. The gene product was produced in Escherichia coli and showed both hydrolysis and transglycosylation activities. The optimal pH for hydrolysis activity was 6.0, and a stable pH range of 5.0-11.0 was found. The enzyme had a temperature optimum of 60 °C. It is specific for α-1,6-glycosidic linkages and had a K m value of 1.45 mM toward pNPGal. When using melibiose as both donor and acceptor of galactose, Gal36A4 showed the transfer ratio of 23.25 % at 96 h. With respect to acceptor specificity, all tested monosaccharides, disaccharides, and oligosaccharides except for D-xylose and L-arabinose were good acceptors for transglycosylation. Thus, Gal36A4 may find diverse applications in industrial fields, especially in the food industry.
authors: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, 100081, Beijing, People's Republic of China.
authors: Huimin
authors: H
authors: Wang
authors: Rui
authors: R
authors: Ma
authors: Pengjun
authors: P
authors: Shi
authors: Xianli
authors: X
authors: Xue
authors: Huiying
authors: H
authors: Luo
authors: Huoqing
authors: H
authors: Huang
authors: Yingguo
authors: Y
authors: Bai
authors: Peilong
authors: P
authors: Yang
authors: Bin
authors: B
authors: Yao
mesh_terms: D056450:Alicyclobacillus / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D004795:Enzyme Stability; D006031:Glycosylation; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D016366:Open Reading Frames; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D013379:Substrate Specificity; D000519:alpha-Galactosidase / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D009844:Oligosaccharides; D011994:Recombinant Proteins; D000519:alpha-Galactosidase