摘要
旨在获得能降解玉米糠木聚糖的阿拉伯呋喃糖苷酶,并对其进行异源表达和酶学性质分析。稻平脐蠕孢(Bipolaris oryzae)是重要的植物病原菌,它编码、分泌糖苷水解酶降解植物的木质纤维素利于侵袭感染。从稻平脐蠕孢中克隆得到一个新的GH43家族阿拉伯呋喃糖苷酶基因BoAra43A并将其在大肠杆菌中成功表达。分析发现重组酶BoAra43A的最适温度为50℃,在40℃处理2 h后活力还剩90.6%活性;最适pH为5.0,在pH 3.0-9.0比较稳定,可保持80%以上的酶活力。BoAra43A可降解富含侧链的异质性木聚糖如小麦阿拉伯木聚糖(WAX)、玉米糠(CX)及其碱提物(CX-NaOH)和寡糖如A2,3XX、XA2,3XX、AA2,3AA/AAA3A中的阿拉伯糖,推断其能降解阿拉伯糖双取代的木聚糖中α-(1→3)连接的阿拉伯糖。PsAra43A是来源于Paenibacillus sp.E18的GH43阿拉伯呋喃糖苷酶,降解异质性木聚糖上的单取代阿拉伯糖侧链。使用BoAra43A预先处理CX、再和阿拉伯呋喃糖苷酶PsAra43A反应,两种酶之间具有较强的协同作用,协同度为1.34。
The aim of this study is to obtain an arabinofuranosidase which can degrade the corn bran xylan,to heterologously express the gene,and to characterize the enzymatic properties.Bipolaris oryzae is an important plant pathogen which encodes and secrets glycoside hydrolases to degrade plant lignocellulose to facilitate its invasion.A novel gene BoAra43A gene encoding a GH43 arabinofuranosidase was cloned from B.oryzae and successfully expressed in Escherichia coli.The optimal temperature of the recombinant enzyme BoAra43A was 50℃.The enzyme retained 90.6% activity after being treated at 40℃ for 2 h;its optimal pH was 5.0,and it was quite stable at pH 3.0-9.0 and maintained over 80% activity.BoAra43A degraded heterogeneous xylan rich in side chains such as wheat arabinoxylan(WAX),corn bran xylan(CX),and its alkaline extracted xylan components(CX-NaOH).It also degraded oligosaccharides such as A2,3XX,XA2,3XX,and AA2,3AA/AAA3A.It was deduced that BoAra43A hydrolyzed the α-(1→3)linkage of the doubly substituted xylan side chain.PsAra43A was a GH43 arabinofuranosidase from Paenibacillus sp.E18,which degraded the singly substituted arabinose side chain in the heterogeneous xylan.Sequentially using BoAra43A pre-processing CX and then reacting with another arabinofuranosidase PsAra43A,the two enzymes had synergistic effect in hydrolyzing CX with a degree of synergy 1.34.
作者
邢亚欣
黄火清
苏小运
XING Ya-xin;HUANG Huo-qing;SU Xiao-yun(Key Laboratory of Feed Biotechnology,Ministry of Agriculture,Feed Research Institute,Chinese Academy of Agricultural Sciences,Beijing 100081)
出处
《生物技术通报》
CAS
CSCD
北大核心
2020年第4期84-92,共9页
Biotechnology Bulletin
基金
国家自然科学基金面上项目(31672458)。
