摘要
为探究植物细胞壁降解酶高效降解细胞壁的机制,用RT-PCR方法对Q7-31T菌株植物细胞壁降解酶基因片段进行克隆,使用Prot-Param、SOPMA、ProtScale Server等软件对质谱鉴定结果进行生物学分析。结果表明:将Q7-31T菌株植物细胞壁降解相关酶归为GH5家族内切葡聚糖酶、GH7家族内切葡聚糖酶、GH7家族外切葡聚糖酶和GH10家族内切木聚糖酶4类酶。这些相关酶类为中等分子量大小,二级结构由α-螺旋、延伸链、β-转角和无规则卷曲4种元件构成,其中无规则卷曲的数量最高;均为亲水性酶,磷酸化位点比例较高,存在1~2个糖基化位点;均存在较高比例的催化结构域,三级结构呈中空的C字形。结论:少量的糖基化位点、高比例的催化结构域、多变的三维构象、大量的磷酸化位点与高效的协同作用方式可能决定Q7-31T菌株的植物细胞壁降解酶对细胞壁的高效降解。
For exploring the mechanism of high-efficiency plant cell wall degradation process based on plant cell wall degrading enzymes from Fusarium strain Q7-31 T,for the gene cloning and biological analysis,the methods respectively were PCR amplification and some bioinformatic softwares such as ProtParam,SOPMA and ProtScale Server.Results:The plant cell wall degrading enzymes in Q7-31 Tare classified as:GH5family endoglucanase,GH7 family endoglucanase,GH7 family exo-glucanase and GH10 family endoxylanase,which are consistent with mass spectrometry.The enzymes are medium molecular size,and the secondary structure consists of four elements:α-helix,extended strand,β-turn and random coil,of which random coil is most abundant;four enzyme classes are hydrophilic enzymes,and have higher proportion of phosphorylation sites.There are 1~2glycosylation sites.Four enzymes are present in a higher proportion of catalytic domains and the tertiary structure of a hollow "C"shape.Conclusion:A small number of glycosylation sites,high proportion of catalytic domains,changeable threedimensional conformations,large number of phosphorylation sites and high-efficiency synergism probably determine the high-efficiency degradation of plant cell wall degrading enzymes in strain Q7-31 T.
引文
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