open access

https://hdl.handle.net/2115/87269

Substrate specificity of glycoside hydrolase family 1 β-glucosidase AtBGlu42 from Arabidopsis thaliana and its molecular mechanism

英語

Arabidopsis thaliana

2021-11-22

Bioscience, Biotechnology and Biochemistry

86(2)

231-245

Plants possess many glycoside hydrolase family 1 (GH1) β-glucosidases, which physiologically function in cell wall metabolism and activation of bioactive substances, but most remain uncharacterized. One GH1 isoenzyme AtBGlu42 in Arabidopsis thaliana has been identified to hydrolyze scopolin using the gene deficient plants, but no enzymatic properties were obtained. Its sequence similarity to another functionally characterized enzyme Os1BGlu4 in rice suggests that AtBGlu42 also acts on oligosaccharides. Here, we show that the recombinant AtBGlu42 possesses high kcat/Km not only on scopolin, but also on various β-glucosides, cellooligosaccharides, and laminarioligosaccharides. Of the cellooligosaccharides, cellotriose was the most preferred. The crystal structure, determined at 1.7 A resolution, suggests that Arg342 gives unfavorable binding to cellooligosaccharides at subsite +3. The mutants R342Y and R342A showed the highest preference on cellotetraose or cellopentaose with increased affinities at subsite +3, indicating that the residues at this position have an important role for chain length specificity.

学術雑誌論文

Accepted Manuscript

This is a pre-copyedited, author-produced version of an article accepted for publication in Bioscience biotechnology and biochemistry following peer review. The version of record Shu Horikoshi, Wataru Saburi, Jian Yu, Hideyuki Matsuura, James R Ketudat Cairns, Min Yao, Haruhide Mori, Substrate specificity of glycoside hydrolase family 1 β-glucosidase AtBGlu42 from Arabidopsis thaliana and its molecular mechanism, Bioscience, Biotechnology, and Biochemistry, Volume 86, Issue 2, February 2022, Pages 231-245 is available online at: https://doi.org/10.1093/bbb/zbab200.

1347-6947