The Research On Function Of Gene Slr1649 From Synechocystis Sp. PCC 6803

Synechocystis sp. PCC6803 belongs to the Cyanophyceae, is a kind of prokaryote, which is mixotrophic and capable of assimilating the optical energy and organic substance. Along with the development of Cyanophyceae gene engineering, Synechocystis sp. PCC6803 has become an important bacteria tool and model organisms in the research of photosynthesis mechanism. Phycobiliprotein is an important light-harvesting protein of algae and has important biological significance for the growth and reproduction of the algae cell. In vivo, the process of phycobilisome assembly and the phycobiliprotein biosynthesis is highly ordered and catalyzed by a series of enzymes. In 2006, Shen had demonstrated that the protein encoded cpcT from Synechococcus PCC7002 play a role as a lyase to catalyze the biosynthesis of Phycocyanin. By allogenic analysis, it is easily to find the similarities between sequence of slr1649 from Synechocystis sp. PCC6803 and cpcT is 50%. In order to study its biological function, two methods was adopted to construct homologous knock-out mutation vector. The difference between these two methods is all about the different homologous sequence. Synechocystis sp. PCC6803 has the characteristics of natural transformation to absorb exogenous DNA, which is knock-out mutation vector in this experiment. By doing this, we could screen out the slr1649 knock-out mutant strain through the resistance molecular marker. By observing the cultivating phenotype changes of mutant strain contrasted with wild strain, function of the gene slr1649 could be forecasted preliminarily.The biological function of slr1649 was analyzed by observing and contrasting the changes of the phenotypic characters of the mutant compared to the wild type strain. Combining the allogenic analysis with the sequence of cpcT, the Main function of the protein encoded by slr1649 is more likely to specifically attach PCB to cysteine 153 of CpcB. which is of great significance to the phycobiliprotein biosynthesis.Nowadays, the research on the phycobiliprotein lyase is very extensive; genes such as cpcT, cpeT, cpcE and cpcF are all proved to have such catalytic activity. As long as the phycobiliprotein has the role as a light-harvesting component, it is of great importance to understand and grasp its biosynthetic mechanism. Also such study will be instructive and meaningful to the governance of water blooms caused by algal.