title: [Characterization of metalloprotease of Slr0643 and Sll0862, the S2P homologs from Synechocystis sp. PCC6803].
abstract: 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 beta-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.
  
  
  CONCLUSIONS
  The site-2 protease homologs in Synechocystis sp. PCC6803 have metalloprotease activity.
authors.affiliation: College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640, China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Qin
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.forename: Gu
authors.initials: G
authors.lastname: Chen
mesh_terms: D045726:Metalloproteases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification; D046939:Synechocystis / Q000201:enzymology*
chemical_list: D011994:Recombinant Proteins; D045726:Metalloproteases