Characterization of metalloprotease of Slr0643 and Sll0862, the S2P homologs from Synechocystis sp. PCC6803
集胞藻PCC6803中S2P同源蛋白Slr0643及Sll0862 金属蛋白酶活性的体外鉴定

Objective]It is a conserved mechanism in bacteria that metalloprotease site-2 protease(S2P) cleaves transmembrane anti-sigma factor to release sequestered sigma factor in response to extracytoplasmic stress.However,the function of site-2 protease homologs in cyanobacteria remains elusive,so we investigated the metalloprotease activity of Slr0643 and Sll0862,the site-2 protease homologs from Synechocystis sp.PCC6803.Methods] Recombinant Slr0643 and Sll0862 were constructed and overexpressed in Escherichia coli BL21(CE3).Their protease activities were tested against β-casein and then resolved on SDS-PAGE.Results] Results from caseinolytic assay indicated that Slr0643 and Sll0862 have proteolytic activity which is blocked by o-phenanthroline,a metalloprotease inhibitor.These metalloprotease activity of Slr0643 and Sll0862 in vitro provide the foundation for futher analysis of their substrates in vivo.Conclusion] The site-2 protease homologs in Synechocystis sp.PCC6803 have metalloprotease activity.