【摘要】 对稻瘟病菌一个假定的α-1,2-甘露糖苷酶MgManⅠ生物信息学进行分析的结果表明,该蛋白与海枣曲霉、桔青霉等丝状真菌的已知α-1,2-甘露糖苷酶(EC 3.2.1.113)氨基酸序列具有高度同源性,并具有其相同的活性中心位点.基序分析表明,该蛋白可能含有4个N-糖基化位点、3类19个磷酸化位点和12个N-肉豆蔻酰位点.该蛋白的相对分子质量预测为58.2 ku,理论等电点pI为5.17,并且为细胞外分泌蛋白,信号肽剪切位点为21A和22S之间.系统发育分析表明:MgManⅠ与丝状真菌中的海枣曲霉、桔青霉α-1,2-甘露糖苷酶之间亲缘关系最近,形成一大类;动物的α-1,2-甘露糖苷酶与植物的α-1,2-甘露糖苷酶分别聚成二大类;酿酒酵母α-1,2-甘露糖苷酶ScManⅠ与丝状真菌不同,单独成为一类.进一步以已知结构的PcManⅠ为模板,通过同源建模得到的三维结构图形基本反映了MgManⅠ的空间构象,为深入研究该蛋白的生化特性和生物学功能奠定了基础.更多还原

【Abstract】 The bioinformatic tools were used to analyze a hypothetical 1,2-alpha-mannosidase(MgManⅠ) of Magnaporthe grisea.The results showed that the MgManⅠ is highly homologous to known 1,2-alpha-mannosidase(EC 3.2.1.113) protein from filamentous fungi such as Aspergillus phoenicis and Penicillium citrinum,with the same activity center sites.Motif analysis showed that the protein may contain 4 N-glycosylation sites,19 phosphorylation sites and 12 N-myristoylation sites.The protein is predicted to have a signal cleavage site between 21A and 22S,and be secreted to extracellular compartments,with a relative molecular weight of 58.2 ku.The predicted pI value is 5.17.Phylogenetic analysis showed that the evolutionary distance was the closest between MgManⅠ and 1,2-alpha-mannosidases from filamentous fungi,such as P.citrinum and A.phoenicis,which were clustered in the same clade,distinguishing from animal clade and plant clade.Interestingly,1,2-alpha-mannosidase from Saccharomyces cerevisiae forms a unique clade different from the filamentous fungus clade.The three-dimensional structural graphic was also constructed via homologous modeling based on the known structure of PcManⅠ,which well reflects the space conformation of MgManⅠ.In conclusion,the results of the bioinformatic analysis will facilitate to understand the structure and function of this putative 1,2-alpha-mannosidase in the fungus.更多还原