School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, People's Republic of China.
Biotechnol Lett. 2013 Dec;35(12):2073-9. doi: 10.1007/s10529-013-1298-z. Epub 2013 Aug 2.
A mesophilic Aspergillus oryzae xylanase (AoXyn11A) belongs to glycoside hydrolase family 11. Hydrogen bonds and a disulfide bridge were introduced between the N-terminus extension and the β-sheet A2 of AoXyn11A, which were located in the corresponding region of a hyperthermostable xylanase. The mutants were designated as AoXyn11A(C5) and AoXyn11A(C5-C32), respectively. The thermostabilities of AoXyn11A and the mutants were assessed by the molecular dynamics simulations. After being incubated at 55 °C for 30 min, AoXyn11A(C5-C32) retained 49 % of its original activity, AoXyn11A(C5) retained 12 % and AoXyn11A retained 3 %. The interactions between the N-terminus extension and the β-sheet A2 were analyzed in depth: there was enhancement of the interactions between the N-terminus extension and the β-sheet A2 of AoXyn11A that improved its thermostability.
一株嗜温米曲霉木聚糖酶（AoXyn11A）属于糖苷水解酶家族 11。通过在 AoXyn11A 的 N 端延伸区和 β-片层 A2 之间引入氢键和二硫键，该酶的结构与一个嗜热木聚糖酶的相应区域相匹配。突变体分别被命名为 AoXyn11A(C5)和 AoXyn11A(C5-C32)。通过分子动力学模拟评估了 AoXyn11A 及其突变体的热稳定性。在 55°C 下孵育 30 分钟后，AoXyn11A(C5-C32)保留了其原始活性的 49%，AoXyn11A(C5)保留了 12%，AoXyn11A 保留了 3%。深入分析了 N 端延伸区与 β-片层 A2 之间的相互作用：增强了 AoXyn11A 的 N 端延伸区与 β-片层 A2 之间的相互作用，从而提高了其热稳定性。
