InterPro: IPR003284 Salmonella virulence plasmid 65kDa B protein

Salmonella typhimurium contains a 90kb plasmid that is associated with virulence [1]. This plasmid encodes at least 6 genes needed by the bacterium for invading host macrophages during infection. These include the 70kDa mkaA protein [2], a recognised virulence factor, and more recently described, four spv genes under the control of a regulator [3]. The spv genes are induced under carbon-poor conditions at a stationary phase of growth, and their expression is under the control of both the spvR regulator, and the katF locus in Salmonella. It has been proposed that individual spv proteins may be required at different time points during infection [4].

SpvB is a 65kDa protein that has been localised to the bacterial cytoplasm [4]. Its expression peaks during early stationary phase, but declines as the latent phase of the infection is reached, suggesting a role in initiating virulence.