基于残基相互作用网络比对的木聚糖酶热稳定性研究

Research on the Xylanase Thermostability Based on Residue Interaction Network Alignment

研究木聚糖酶的耐热机制能够提升工业生产效率和经济效益。本文使用SI-MAGNA残基相互作用网络比对算法,对来自嗜热子囊菌的耐热型木聚糖酶(Ta-XYNA)和来自变铅青链霉菌(SlXln A)的常温型木聚糖酶进行网络比对,以探究影响两者结构稳定性和热稳定性的因素。通过比对结果分析证实,(βα)8-桶结构的低序列保守性及β折叠对结构稳定性的作用;发现Sl-Xln A的loop1区域中独有1个3_(10)-螺旋结构影响了结构稳定性;Ta-XYNA中的α_1'短螺旋结构和相对较短的β_4α_4-loop区域有助于提升其结构稳定性和酶的热稳定性;推测Ta-XYNA的β_4α_4-loop区域中独有的氢键转折结构、Sl-XlnA的loop6区域中独有的2个β桥结构可能引起空间结构的细微差异,从而影响酶的热稳定性。

Studying the heat resistance mechanism of xylanase can improve industrial production and economic efficiency. In this paper,we used the residue interaction network alignment algorithm SIMAGNA for the network alignment of Thermoascus aurantiacus xylanase（ Ta-XYNA） and Streptomyces lividans xylanase（ Sl-Xln A）,to explore the factors that affect the structural stability and thermal stability of the two proteins. By analyzing the results of the alignment, we confirmed the low sequence conservation of the（ βα）8-barrel structure and the effect of the β-strand on the structural stability. We found a unique 310-helix structure in the loop1 region of Sl-Xln A that affects the structural stability. We also found an α1’ short helix structure and a relatively short β4α4-loop region in Ta-XYNA,which enhance the structural stability and the thermostability of the enzyme. And we inferred that the unique hydrogen bonding transition structure in the β4α4-loop region of Ta-XYNA and two β-bridge structures unique to the Sl-XlnA loop6 region may cause a slight difference in the spatial structure,thus affecting the thermostability of the enzyme.