红色亚栖热菌耐热木聚糖酶的克隆表达及生物信息学分析

摘要

This paper reports a novel GH10 xylanase produced by thermophilic bacterium Meiothermus rubber. The xylanase gene was cloned from the genomic DNA of a new isolate of M. rubber, and overexpressed in Escherichia coli, and recombinant Mru xylanase was purified and characterized. Mru xylanase efficiently released xylose from oat spelt xylan at 55-75 ℃ with the highest activity at 65℃. The bioinformatics analysis indicated that Mru xylanase shared≥61% similari⁃ties with the xylanases of Meiothermus spp., but≤49% similarities with the other GH10 xylanases in database. The predic⁃tion of the Mru xylanase structure revealed that the conserved sequences for GH10 xylanases mainly occurred in theβ⁃sheets and few identities were observed in α⁃helixes. Mru xylanase represents a type of heat⁃stable G10 xylanase.%从自主分离的Meiothermus． rubber菌株的基因组中克隆到木聚糖酶基因，并进行了超量表达、重组酶的纯化和酶学性质研究。结果表明，重组木聚糖酶Mru是热稳定性酶，最适反应温度为65℃，能够有效降解木聚糖产生木糖和木二糖。生物信息学分析发现，木聚糖酶Mru与数据库中来自亚栖热菌的木聚糖酶的同源性为60％～100％。在木聚糖酶Mru的结构模型中，GH10木聚糖酶的保守位点大多位于β折叠，α螺旋保守性很低。本研究揭示，木聚糖酶Mru代表一类新型热稳定性GH10木聚糖酶。