嵌合纤维小体的空间结构与汽爆玉米秸秆酶解动力学特征研究  

DYNAMIC CHARACTERS OF STRUCTURE OF DESIGNER CELLULOSOME AND ENZYMOLYSIS OF STEAM EXPLOSION CORN STOVER

作　　者：杜济良[1] 刘磊[1] 万平[1] 李雅轩[1] 李娟娟 田沈[1] Du Jiliang;Liu Lei;Wan Ping;Li Yaxuan;Li Juanjuan;Tian Shen(College of Life Science,Capital formal University,Beijing 100048,China)

机构地区：[1]首都师范大学生命科学学院,北京100048

出　　处：《太阳能学报》2021年第12期292-296,共5页Acta Energiae Solaris Sinica

基　　金：国家科技支撑计划(2019YFB1503802);国家自然科学基金面上项目(31971202)。

摘　　要：为探究嵌合纤维小体的空间结构对其酶解动力学性能的影响,通过胞外自组装,将纤维素酶分别锚定在不同支架蛋白上,从而构建出具有不同空间结构的人工纤维小体。对比分析嵌合纤维小体和游离酶的热稳定性差异,并以汽爆玉米秸秆为底物进行酶解动力学分析,获得米氏常数(K_(m))、最大反应速率(V_(max))和底物反馈抑制常数(K)。结果显示,纤维素酶与支架蛋白的结合能使其热敏感度降低且热稳定性提高。此外,二级支架蛋白嵌合纤维小体水解汽爆玉米秸秆的K_(m)=0.02 mg/m L、V_(max)=19 mg/(m L·min)、K=0.04 mg/L,说明二级支架蛋白使酶与底物的亲和力比简单结构嵌合纤维小体提高19.8%,进而证明嵌合纤维小体的复杂空间结构能优化其酶解动力学特征、提高纤维素酶的热稳定性。To investigate the effect of the structure of designer cellulosome on the enzymatic kinetics,the designer cellulosome with different structures were constructed through extracellular self-assembly by anchoring cellulases to the primary scaffoldin Scaf I-CBM3a or the adaptor scaffoldin Scaf II-Cip A and Scaf II-Sca B.The thermostability difference between designer cellulosome and free enzymes was analyzed comparatively,the enzymatic kinetic analysis of steam explosion corn stover was carried out,the Michaelis constant(K_(m)),maximum reaction rate(V_(max))and substrate feedback inhibition constant(K)were obtained finally.As the results,the binding of cellulase and scaffold protein can reduce its thermal sensitivity and improve its thermal stability.The steam explosion corn stover of designer cellulosome with secondary scaffold protein has the value of K_(m)=0.02 mg/m L,V_(max)=19 mg/(m L·min),K=0.04 mg/L.It indicates that the affinity between enzymes and substrates enhanced by secondary scaffold proteins is higher than that of the simple structure,K_(m)increases by 19.8%.The complex spatial structure of designer cellulosome can change the enzymatic kinetics characteristics,even improve the thermostability of the cellulase.

关 键 词：嵌合纤维小体 纤维素酶 热稳定性 动力学 玉米秸秆 纤维素乙醇 

分 类 号：TK513.5[动力工程及工程热物理—热能工程]