The DamX protein of Escherichia coli and Salmonella enterica.

We recently showed that disruption of damX causes bile sensitivity in Salmonella enterica. The damX gene is part of an operon that contains genes with heterogeneous functions: DNA adenine methylation, biosynthesis of aromatic compounds, carbohydrate metabolism, and tRNA charging. The damX gene encodes a protein with a predicted size of 46 kDa. In Salmonella, DamX is found in the inner membrane of both dividing and non-dividing cells. The DamX protein contains a peptidoglycan-binding SPOR domain, and accumulates in the E. coli septal ring. E. coli mutants lacking DamX are bile-sensitive like their Salmonella counterparts.