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The PmrA/PmrB and RcsC/YojN/RcsB systems control expression of the Salmonella O‐antigen chain length determinant
Author(s) -
Delgado Mónica A.,
Mouslim Chakib,
Groisman Eduardo A.
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05069.x
Subject(s) - protein data bank (rcsb pdb) , biology , salmonella enterica , mutant , lipid a , gene , transcription (linguistics) , microbiology and biotechnology , enterobacteriaceae , bacteria , salmonella , biochemistry , genetics , escherichia coli , linguistics , philosophy
Summary The lipopolysaccharide (LPS) is the outermost component of the cell envelope in Gram‐negative bacteria. It consists of the hydrophobic lipid A, a short non‐repeating core oligosaccharide and a distal polysaccharide termed O‐antigen. We report here that the PmrA/PmrB and RcsC/YojN/RcsB two‐component systems of Salmonella enterica serovar Typhimurium independently promote transcription of the wzz st gene, which encodes a protein that determines the chain length of the O‐antigen. We show that the regulatory proteins PmrA and RcsB footprint partially overlapping regions of the wzz st promoter stimulating transcription from the same start site. Induction of the PmrA/PmrB or RcsC/YojN/RcsB systems increased the fraction of LPS molecules containing 16–35 O‐antigen subunits, leading to heightened resistance to serum. The LPS of a rcsB null mutant exhibited an altered mobility in the O‐antigen subunits attached to the lipid A‐core region when separated on a SDS/PAGE gel, suggesting that RcsB may regulate additional LPS genes. Inactivation of the wzz st gene eliminated the enhanced swarming behaviour exhibited by the rcsB mutant. That multiple regulatory systems control wzz st expression suggests that the Wzz st protein is required under different environmental conditions.