DsbL and DsbI contribute to periplasmic disulfide bond formation in Salmonella enterica serovar Typhimurium.
Disulfide bond formation in periplasmic proteins is catalysed by the DsbA/DsbB system in most Gram-negative bacteria. Salmonella enterica serovar Typhimurium also encodes a paralogous pair of proteins to DsbA and DsbB, DsbL and DsbI, respectively, downstream of a periplasmic arylsulfate sulfotransferase (ASST). We show that DsbL and DsbI function as a redox pair contributing to periplasmic disulfide bond formation and, as such, affect transcription of the Salmonella pathogenicity island 1 (SPI1) type three secretion system genes and activation of the RcsCDB system, as well as ASST activity. In contrast to DsbA/DsbB, however, the DsbL/DsbI system cannot catalyse the disulfide bond formation required for flagellar assembly. Phylogenic analysis suggests that the assT dsbL dsbI genes are ancestral in the Enterobacteriaceae, but have been lost in many lineages. Deletion of assT confers no virulence defect during acute Salmonella infection of mice.
Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.
Dongxia
D
Lin
Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.
Byoungkwan
B
Kim
College of Medicine, University of Illinois, Urbana, IL 61801, USA.|Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.
James M
JM
Slauch
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004220:Disulfides / Q000378:metabolism*; D005260:Female; D017353:Gene Deletion; D005798:Genes, Bacterial; D051379:Mice; D008807:Mice, Inbred BALB C; D010084:Oxidation-Reduction; D033903:Periplasmic Proteins / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics; D012481:Salmonella Infections, Animal / Q000382:microbiology; D012486:Salmonella typhimurium / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D015534:Trans-Activators / Q000235:genetics; D014158:Transcription, Genetic; D014774:Virulence / Q000235:genetics / Q000502:physiology
D001426:Bacterial Proteins; D004220:Disulfides; C102236:HilA protein, Salmonella; D033903:Periplasmic Proteins; C419942:Spi1 protein, Salmonella; D015534:Trans-Activators