固氮红细菌原位中心捕光复合体LH1特异性解离  

Specific Dissociation of the Membrane Bounded Core Light Harvesting Complex 1 from Rhodobacter azotoformans

作　　者：岳慧英 杨素萍[2] 赵春贵[2] YUE Huiying;YANG Suping;ZHAO Chungui(College of Basic Medical Sciences,Shanxi University of Chinese Medicine,Jinzhong 030619,China;Department of Bioengineering and Biotechnology,Huaqiao University,Xiamen 361021,China)

机构地区：[1]山西中医药大学基础医学院,山西晋中030619 [2]华侨大学生物工程与技术系,福建厦门361021

出　　处：《山西大学学报（自然科学版）》2022年第5期1333-1341,共9页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(31070054);山西中医药大学科技创新能力培育计划(2020PY-JC-04);山西省教育厅项目(2020L0414)。

摘　　要：紫细菌的光合单元从属于膜整合蛋白,在纯化过程中去垢剂会破坏光合单元核心捕光复合体(LH1)的结构,导致LH1制备困难,但是去垢剂分子如何影响LH1的结构,很少提及。采用透析法和光谱法系统地研究了温和型两性去垢剂LDAO浓度和作用时间对固氮红细菌(Rhodobacter azotoformans)原位膜上LH1构象的影响,结果表明LDAO体积分数>0.1%能引起R. azotoformans原位膜LH1不可逆地破坏,0.05%~1%LDAO均导致LH1的特征吸收峰A875下降,表明LH1发生了解离,解离程度与LDAO浓度呈正相关。通过硫酸铵盐析和DEAE阴离子交换层析纯化色素蛋白复合体进行结果验证,结果表明1%LDAO增溶后只分离到了反应中心(RC)和外周捕光复合体(LH2),而采用0.05%LDAO增溶后获得了RC-LH1。综合分析LDAO与原位膜上LH1的作用规律得出0.05%LDAO浓度可用于进行R. azotoformans LH1的制备。本研究可为LH1的纯化、保存及结晶提供依据,为研究光合单元和光合作用机理奠定基础。The photosynthetic apparatus of purple bacteria belongs to integral membrane proteins, and detergent could destroy the structure of core light harvesting complex(LH1) photosynthetic apparatus during its purification, resulting in the difficulty of LH1preparation. However, how the detergent affected the structure of LH1 was rarely mentioned. The effects of mild amphoteric detergent LDAO concentration and reaction time on the conformation change of membrane bound LH1 in Rhodobacter azotoformans were studied by dialysis and spectroscopic methods. The results showed that the concentration of LDAO higher than 0. 1%(V/V)could induce LH1 dissociation. A875was decreased in LDAO concentration of 0. 05%-1%, indicating that LH1 was dissociated,and the dissociation degree was positively correlated with the concentration of LDAO. The results were verified by ammonium sulfate precipitation and DEAE anion exchange chromatography. Only reaction center complex(RC) and peripheral light harvesting complex 2(LH2) were obtained in 1% LDAO treated sample, while only RC-LH1 was obtained in 0. 05% LDAO treated sample.From the comprehensive analysis of the interaction between LDAO and membrane bounded LH1, we can conclude that 0. 05% LDAO can be used for the preparation of LH1 in R. azotoformans. The present study provides a reference to the purification, storage and crystallization of LH1, and lays a foundation to the further study of photosynthetic apparatus and photosynthetic mechanism.

关 键 词：固氮红细菌 色素蛋白复合体 温和型两性去垢剂LDAO 核心捕光复合体 

分 类 号：Q935[生物学—微生物学]