米曲霉木糖醇脱氢酶的分子模建与对接

Homology modeling and molecular docking of xylitol dehydrogenase from Aspergillus Oryzae

摘要:

摘要:【目的】研究米曲霉木糖醇脱氢酶基因的结构与功能。【方法】克隆测序来源于米曲霉的木糖醇脱氢酶(XDH)基因，利用Swiss-MODEL 和Modeller 对XDH 进行三级结构模建，通过PROCHECK和Prosa2003 对得到的4 个目标模型进行评价，从中得到一个最佳模型。在同源建模的基础上，通过分子对接软件Molsoft ICM-Pro，对辅因子进行对接，预测了XDH 与NAD+、Zn2+作用的相关残基。寻找底物木糖醇与XDH 结合的可能活性口袋，用Molsoft 模拟XDH 与木糖醇的对接，

Abstract:

Abstract:［Objective］We investigated the structure model and function of xylitol dehydrogenase from Aspergillus oryzae．［Methods］ Xylitol dehydrogenase (XDH) gene from Aspergillus oryzae was cloned and sequenced．We constructed four tertiary structure models of XDH by homology modeling with Swiss-MODEL and Modeller and obtained the best quality model by evaluation of PROCHECK and Prosa2003. The dockings of NAD+，Zn2+ and xylitol with XDH were performed by Molsoft program． ［Results］ Structure analysis suggested that XDH was a member of medium-chain dehydrogenase/reductase (MDR) family．This was supported by the presence of the zinc-containing alcohol dehydrogenase signature and a typical alcohol dehydrogenase Rossmann fold pattern composed by NAD + binding domain present in MDR superfamily．The molecular docking indicated that amino acid residues Asp206，Arg211，Ser255，Ser301 and Arg303 in XDH binding domain had hydrogen bonding with NAD + ，His72 and Glu73 in catalytic domain had hydrogen bonding with Zn2 + ，Ile46，Ile349，Lys350 and Thr351 in catalytic domain had hydrogen bonding with xylitol． ［Conclusion］ These key amino acid residues might play a vital role in the XDH catalytic reaction and can instruct the further directed modification of XDH．