紫色光合细菌捕获太阳能的分子机理

Molecular Mechanism of Solar Energy Harvesting by Purple Photosynthetic Bacteria

光合作用是地球上最重要的化学反应,生物体通过它捕获太阳能,转为化学能供生长繁殖需要.光合细菌是地球上最早出现的具有原始光能合成体系的微生物,其光合反应中心是一个由多种色素分子与蛋白质以非共价键方式结合的、具有特定构象的色素-蛋白复合体-光反应中心RC(Reaction center)和LH(Light Harvesting),光能通过电荷分离及电子转移反应转化为化学能,其效率是当前人工模拟远远不能及的.本文综述了紫色光合细菌捕获太阳能的分子结构、作用机理的研究进展,并结合作者在R.sphaeroides LHII蛋白组份同源及异源基因表达方面的研究结果进行相应的分析,明确了Rhodobacter sphaeroides基因组中同源基因puc2BA的表达特点和功能,Rhodovulum sulfidophilum pucsBA与R.sphaeroides pufBA能够同时在R.sphaeroides中表达,能同时形成LHII和LHI,并具有能量传递功能.

Photosynthesis is arguably the most important biological process,by it organisms harvest solar energy and transfer it into chemical energy for growth and reproduction.The photosynthetic bacteria are the earliest microbe with photosynthesis found on earth.The photosynthetic apparatus of purple bacteria is a nanometric assembly in the intracytoplasmic membranes and consists of pigment-protein complexes,the photosynthetic RC（Reaction center） and LH（Light harvesting）.The primary processes of photosynthesis involve absorption of photons by LH complexes,transfer of excitation energy from the LH complexes to the photosynthetic RC,where the primary energy conversion takes place.The researches on molecular structure and mechanism of purple photosynthetic bacteria harvesting solar energy were summarized.Molecular biology techniques and spectroscopic analysis were applied to research the expression and function of puc2BA and pucsBA by the authors,and it was concluded that the puc2BA gene was normally expressed in Rhodobacter sphaeroides,the pucsBA gene of Rhodovulum sulfidophilum and the pufBA gene of R.sphaeroides were expressed in R.sphaeroides,and the heterologous LHII and native LHI were produced and assembled in the membrane.