生物学杂志

生物学杂志 ›› 2022, Vol. 39 ›› Issue (3): 78-.doi: 10.3969/j.issn. 2095-1736.2022.03.078

• 研究报告 • 上一篇    下一篇

不同紫细菌外周捕光复合体的特征比较

  

  1. 1. 山西中医药大学 基础医学院， 晋中 030619； 2. 华侨大学 生物工程与技术系， 厦门 361021
  • 出版日期:2022-06-18 发布日期:2022-06-17
  • 通讯作者: 赵春贵，博士，教授，研究方向为资源与环境微生物，E-mail: chungui@hqu.edu.cn
  • 作者简介:岳慧英，博士，讲师，研究方向为资源与环境微生物，E-mail: 2003YHY2003@163.com
  • 基金资助:
    国家自然科学基金项目(31070054)； 山西中医药大学科技创新能力培育计划项目(2020PY-JC-04)； 山西省教育厅项目(2020L0414)

Comparison of the multiple characteristics of the peripheral light-harvesting complexes from different purple bacteria

  1. 1. College of Basic Medical Sciences, Shanxi University of Chinese Medicine, Jinzhong 030619, China;
    2. Department of Bioengineering and Biotechnology, Huaqiao University, Xiamen 361021, China
  • Online:2022-06-18 Published:2022-06-17

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摘要： 为阐明不同紫细菌外周捕光复合体（Light-harvesting complex, LH2）表面电荷及其与膜结合能力强弱等特征,以及LH2光谱特征、结构和功能之间的关系，比较了相同去垢剂浓度下增溶时间、盐析浓度和阴离子交换层析洗脱梯度对两个物种不同LH2的纯化和特征的影响。结果显示，源自Rhodobacter azotoformans 的LH2（A-LH2）分离纯化所需要的增溶时间和盐析浓度低于Rhodopseudomonas palustris的LH2（P-LH2），而洗脱盐度相反，表明A-LH2与内质膜结合能力较弱，易于从膜表面解离下来，疏水性较强，表面负电荷较多。与P-LH2相比，A-LH2中BChl a Qy带蓝移至798和848 nm，分子筛层析洗脱体积较小，说明A-LH2复合体的分子半径较大。色素分析表明，P-LH2中主要类胡萝卜素为3,4-双脱氢玫红品（共轭双键数为12），A-LH2中则为球形烯（共轭双键数为10）。拉曼分析表明球形烯采用平面构象结合到A-LH2中，这种短共轭双键及伸展构象有利于A-LH2的能量传递。为比较不同种属（株）LH2与膜结合能力以及表面电荷差异提供了研究方法，另通过不同种属LH2的比较分析可为利用紫细菌LH2构建人造光电转化装置或人工模拟光合产氢系统等提供材料支持。

关键词: 外周捕光复合体, 固氮红细菌, 沼泽红假单胞菌, 分离纯化, 光谱分析

Abstract: To elucidate the surface charge and membrane binding characteristics of peripheral light harvesting complex 2 (LH2) from different purple bacteria, as well as the relationship between its spectral structure and function characteristics, the effects of solubilization time, salting out concentration and anion exchange chromatography elution gradient on the purification results and characteristics of LH2 from different species were investigated. The results showed that the solubilization time and salting out concentration of the LH2 (A-LH2) from Rhodobacter azotoformans were lower than those of the LH2 (P-LH2) from Rhodopseudomonas palustris, whereas the anion exchange chromatography elution gradient of A-LH2 was higher than that of P-LH2, indicating that A-LH2 had stronger membrane binding ability and was easy to dissociated from membrane, besides, A-LH2 had strong hydrophobicity and more negative surface charge. Compared with that in P-LH2, the characteristic absorption peaks of BChl a Qy in A-LH2 blue shifted to 798 and 848 nm, and the elution volume of A-LH2 in molecular sieve chromatography was slightly smaller, indicating that the molecular size of A-LH2 was larger. Pigment composition analysis showed that 3,4-didehydrorhodopin (conjugated double bonds N=12) was the main carotenoid in P-LH2 whereas spheroidene (conjugated double bonds N=10) was the main carotenoid in A-LH2. Raman spectra analysis indicated that spheroidene adopted a planar conformation bound to proteins in A-LH2, and the shorter conjugated double bonds and an extended conformation were beneficial for energy transferring in A-LH2. This study provided a method for comparing the membrane binding ability and surface charge of LH2 among different species (strains). Meanwhile, the comparative analysis of the LH2 from different purple bacteria could provide theories foundation for the construction of artificial photoelectric conversion device or artificial photosynthetic hydrogen production system by using LH2 from purple bacteria.

Key words: light harvesting complex 2 (LH2), Rhodobacter azotoformans, Rhodopseudomonas palustris, separation and purification, spectral analysis

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