4dz1

Publication Abstract from PubMed

Expansion into new host niches requires bacterial pathogens to adapt to changes in nutrient availability and to evade an arsenal of host defences. Horizontal acquisition of Salmonella Pathogenicity Island (SPI) - 2 permitted the expansion of Salmonella enterica serovar Typhimurium into the intracellular environment of host cells by allowing it to deliver bacterial effector proteins across the phagosome membrane. This is facilitated by the SsrA-SsrB two-component regulatory system and a type III secretion system encoded within SPI-2. SPI-2 acquisition was followed by evolution of existing regulatory DNA, creating an expanded SsrB regulon involved in intracellular fitness and host infection. Here, we identified an SsrB-regulated operon comprising an ABC transporter in Salmonella. Biochemical and structural studies determined that the periplasmic solute-binding component, STM1633/DalS, transports D-alanine and that DalS is required for intracellular survival of the bacteria and for fitness in an animal host. This work exemplifies the role of nutrient exchange at the host-pathogen interface as a critical determinant of disease outcome.

Characterization of DalS, an ATP-binding cassette transporter for D-alanine, and its role in pathogenesis in Salmonella enterica.,Osborne SE, Tuinema BR, Mok MC, Lau PS, Bui NK, Tomljenovic-Berube AM, Vollmer W, Zhang K, Junop M, Coombes BK J Biol Chem. 2012 Mar 14. PMID:22418438^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.