Suzuki Hirokazu, Murakami Ayano, Yoshida Ken-ichi
Organization of Advanced Science and Technology, Kobe University.
Biosci Biotechnol Biochem. 2013;77(8):1709-14. doi: 10.1271/bbb.130279. Epub 2013 Aug 7.
Members of glycoside hydrolase family 1 (GH1) cleave glycosidic linkages with a variety of physiological roles. Here we report a unique GH1 member encoded in the genome of Bifidobacterium adolescentis ATCC 15703. This enzyme, BAD0156, was identified from over 2,000 GH1 sequences accumulated in a database by a genome mining approach based on a motif sequence. A recombinant BAD0156 protein was characterized to confirm that this enzyme alone specifically hydrolyzes p-nitrophenyl-α-L-arabinofuranoside among the 24 p-nitrophenyl-glycosides examined. Among natural glycosides, α-1,5-linked arabino-oligosaccharides served as substrates, but arabinan, debranched arabinan, arabinoxylan, and arabinogalactan did not. A time course analysis of arabino-oligosaccharide hydrolysis indicated that BAD0156 is an exo-acting enzyme. These results suggest that BAD0156 is an α-L-arabinofuranosidase. This is the first report of a GH1 enzyme that acts specifically on arabinosides, providing information on GH1 substrate specificity.
糖苷水解酶家族1（GH1）的成员可切割具有多种生理作用的糖苷键。在此，我们报道了青春双歧杆菌ATCC 15703基因组中编码的一个独特的GH1成员。通过基于基序序列的基因组挖掘方法，从数据库中积累的2000多个GH1序列中鉴定出了这种酶，即BAD0156。对重组BAD0156蛋白进行了表征，以确认该酶单独作用时，在所检测的24种对硝基苯基糖苷中，能特异性水解对硝基苯基-α-L-阿拉伯呋喃糖苷。在天然糖苷中，α-1,5-连接的阿拉伯低聚糖可作为底物，但阿拉伯聚糖、去分支阿拉伯聚糖、阿拉伯木聚糖和阿拉伯半乳聚糖则不能。对阿拉伯低聚糖水解的时间进程分析表明，BAD0156是一种外切酶。这些结果表明BAD0156是一种α-L-阿拉伯呋喃糖苷酶。这是关于一种特异性作用于阿拉伯糖苷的GH1酶的首次报道，为GH1底物特异性提供了信息。
