Oh Gyo Won, Kang Yewon, Choi Chang-Yun, Kang So-Young, Kang Jung-Hyun, Lee Min-Jae Lee, Han Nam Soo, Kim Tae-Jip
Division of Animal, Horticultural and Food Sciences, Graduate School of Chungbuk National University, Cheongju 28644, Republic of Korea.
J Microbiol Biotechnol. 2019 Jan 28;29(1):37-43. doi: 10.4014/jmb.1807.11035.
The gene encoding an α--arabinofuranosidase (BvAF) GH51 from FZB42 was cloned and expressed in . The corresponding open reading frame consists of 1,491 nucleotides which encode 496 amino acids with the molecular mass of 56.9 kDa. BvAF showed the highest activity against sugar beet (branched) arabinan in 50 mM sodium acetate buffer (pH 6.0) at 45°C. However, it could hardly hydrolyze debranched arabinan and arabinoxylans. The time-course hydrolyses of branched arabinan and arabinooligosaccharides (AOS) revealed that BvAF is a unique -hydrolase producing exclusively L-arabinose. BvAF could cleave α-(1,2)- and/or α-(1,3)--arabinofuranosidic linkages of the branched substrates to produce the debranched forms of arabinan and AOS. Although the excessive amount of BvAF could liberate -arabinose from linear AOS, it was extremely lower than that on branched AOS. In conclusion, BvAF is the arabinan-specific exo-acting α--arabinofuranosidase possessing high debranching activity towards α-(1,2)- and/or α-(1,3)-linked branches of arabinan, which can facilitate the successive degradation of arabinan by -α-(1,5)--arabinanase.
来自FZB42的编码α-阿拉伯呋喃糖苷酶（BvAF）GH51的基因被克隆并在……中表达。相应的开放阅读框由1491个核苷酸组成，编码496个氨基酸，分子量为56.9 kDa。BvAF在50 mM醋酸钠缓冲液（pH 6.0）中于45°C时对甜菜（支链）阿拉伯聚糖表现出最高活性。然而，它几乎不能水解去支链的阿拉伯聚糖和阿拉伯木聚糖。支链阿拉伯聚糖和阿拉伯低聚糖（AOS）的时间进程水解表明，BvAF是一种独特的水解酶，仅产生L-阿拉伯糖。BvAF可以切割支链底物的α-(1,2)-和/或α-(1,3)-阿拉伯呋喃糖苷键，以产生去支链形式的阿拉伯聚糖和AOS。尽管过量的BvAF可以从线性AOS中释放阿拉伯糖，但其释放量远低于支链AOS。总之，BvAF是一种阿拉伯聚糖特异性外切α-阿拉伯呋喃糖苷酶，对阿拉伯聚糖的α-(1,2)-和/或α-(1,3)-连接分支具有高去支链活性，可促进α-(1,5)-阿拉伯聚糖酶对阿拉伯聚糖的连续降解。
