Shi Fei, Qin Song, Wang Yin-Chu
The Coastal Zone Bio-Resource Laboratory, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China.
Comp Funct Genomics. 2011;2011:230236. doi: 10.1155/2011/230236. Epub 2011 Aug 29.
Phycobilisome is the major light-harvesting complex in cyanobacteria and red alga. It consists of phycobiliproteins and their associated linker peptides which play key role in absorption and unidirectional transfer of light energy and the stability of the whole complex system, respectively. Former researches on the evolution among PBPs and linker peptides had mainly focused on the phylogenetic analysis and selective evolution. Coevolution is the change that the conformation of one residue is interrupted by mutation and a compensatory change selected for in its interacting partner. Here, coevolutionary analysis of allophycocyanin, phycocyanin, and phycoerythrin and covariation analysis of linker peptides were performed. Coevolution analyses reveal that these sites are significantly correlated, showing strong evidence of the functional and structural importance of interactions among these residues. According to interprotein coevolution analysis, less interaction was found between PBPs and linker peptides. Our results also revealed the correlations between the coevolution and adaptive selection in PBS were not directly related, but probably demonstrated by the sites coupled under physical-chemical interactions.
藻胆体是蓝细菌和红藻中的主要捕光复合体。它由藻胆蛋白及其相关的连接肽组成，藻胆蛋白在光能的吸收和单向传递中起关键作用，连接肽则分别对整个复合体系统的稳定性起关键作用。以往关于藻胆蛋白和连接肽进化的研究主要集中在系统发育分析和选择性进化上。共进化是指一个残基的构象因突变而中断，其相互作用伙伴中选择了补偿性变化。在此，对别藻蓝蛋白、藻蓝蛋白和藻红蛋白进行了共进化分析，并对连接肽进行了共变分析。共进化分析表明，这些位点显著相关，有力地证明了这些残基间相互作用在功能和结构上的重要性。根据蛋白质间共进化分析，发现藻胆蛋白和连接肽之间的相互作用较少。我们的结果还表明，藻胆体中共进化与适应性选择之间的相关性并非直接相关，而是可能由物理化学相互作用下耦合的位点所证明。
