Xuejun Li, Junqi Zhao, Pengjun Shi, Peilong Yang, Yaru Wang, Huiying Luo, Bin Yao
Key Laboratory of Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing 100081, People's Republic of China.
Applied biochemistry and biotechnology 2013 FebA novel β-glucosidase gene, bgl1G5, was cloned from Phialophora sp. G5 and successfully expressed in Pichia pastoris. Sequence analysis indicated that the gene consists of a 1,431-bp open reading frame encoding a protein of 476 amino acids. The deduced amino acid sequence of bgl1G5 showed a high identity of 85% with a characterized β-glucosidase from Humicola grisea of glycoside hydrolase family 1. Compared with other fungal counterparts, Bgl1G5 showed similar optimal activity at pH 6.0 and 50 °C and was stable at pH 5.0-9.0. Moreover, Bgl1G5 exhibited good thermostability at 50 °C (6 h half-life) and higher specific activity (54.9 U mg⁻¹). The K (m) and V (max) values towards p-nitrophenyl β-D-glucopyranoside (pNPG) were 0.33 mM and 103.1 μmol min⁻¹ mg⁻¹, respectively. The substrate specificity assay showed that Bgl1G5 was highly active against pNPG, weak on p-nitrophenyl β-D-cellobioside (pNPC) and p-nitrophenyl-β-D-galactopyranoside (ONPG), and had no activity on cellobiose. This result indicated Bgl1G5 was a typical aryl β-glucosidase.
Xuejun Li, Junqi Zhao, Pengjun Shi, Peilong Yang, Yaru Wang, Huiying Luo, Bin Yao. Molecular cloning and expression of a novel β-glucosidase gene from Phialophora sp. G5. Applied biochemistry and biotechnology. 2013 Feb;169(3):941-9
PMID: 23292244
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