镰刀菌Q7-31T菌株植物细胞壁降解酶系的结构  

Structure of Plant Cell Wall Degrading Enzymes from Fusarium Strain Q7-31T

作　　者：赵联正 谢占玲[1,2] 贾贤卿 

机构地区：[1]青海大学生态环境工程学院,青海西宁810016 [2]青海省高原作物种质资源创新与利用重点实验室,青海西宁810016

出　　处：《贵州农业科学》2015年第5期138-145,共8页Guizhou Agricultural Sciences

基　　金：国家自然科学基金资助项目"Q7-31植物细胞壁降解酶系组成及协同作用研究"(31260021)

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 Q7-31T,for the gene cloning and biological analysis,the methods respectively were PCR amplification and some bioinformatic softwares such as Prot-Param,SOPMA and ProtScale Server.Results：The plant cell wall degrading enzymes in Q7-31T are classified as：GH5 family 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 - 2 glycosylation 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 three-dimensional conformations,large number of phosphorylation sites and high-efficiency synergism probably determine the high-efficiency degradation of plant cell wall degrading enzymes in strain Q7-31T.

关 键 词：镰刀菌 植物细胞壁降解酶 结构 

分 类 号：Q932[生物学—微生物学]