Study On The Surface Protein Properties Of Microcystis Aeruginosa XW01 Cells

In our country, Microcystis has been the dominant cyanobacteria of water blooms, which become an increasingly serious problem, for the serious damage to the ecological environment and human health. Colony aggregation is the key of Microcystis to get ecological advantage. Study of the molecular mechanism of colony aggregation has certain guiding significance for solving the problem of cyanobacterial blooms. At present, the mechanism of colony aggregation, especially the mechanism of interaction between cells, is little known. This article comparatively studied the character of surface layer proteins on Microcystis aeruginosa of unicell and colony aggregation status, in order to find the function of surface layer proteins in the formation and maintain of colony.First transmission electron microscope was used to observe the surface structure of Microcystis aeruginosa XW01 (colony) and Microcystis aeruginosa PCC7806 (unicell). After analysis, we found that the cell wall surface of XW01 was covered by regular hexagon crystal protein (Hexagonal P6), and there is no clear crystal structure on PCC7806. LiCl method was used to extract the surface layers of the two strains of Microcystis aeruginosa. After SDS-PAGE, we found a surface layer protein with about 70KDa molecular weight, whereas no protein was extracted from PCC7806. ESI-TRAP characterized that the protein had a high homology to an unknown function protein in PCC7806, which was numbered for CA089090.1 in GenBank. The gene encoded a new kind of surface layer proteins. Using protein analysis tools TMHMM on the website of Expasy to indicate the transmembrane character, we found that CA089090.1 was a surface layer protein. All of those indicate that surface layer proteins may play an important role in colony aggregation.In order to make clear the role of surface proteins further, we studied elementary gene expression level. By blasted CA089090.1 in NCBI database, we found the high conservative area in cyanobacteria. The specific PCR primers was designed, and amplificated a 689 bp-length clip, which had 95% homology with CA089090.1. Then we used a highly efficient genome walking method TAIL-PCR to amplificate 1002 bp-length clip, which made a foundation for further research of the gene.