SloR-SRE binding to the promoter is cooperative.

is a commensal member of the plaque microbiome. It is especially prevalent when dietary sugars are available for fermentation, generating acid byproducts that lower plaque pH and foster tooth decay. can survive in the transient conditions of the mouth, in part because it can regulate the uptake of manganese and iron during periods of feast when metal ions are available, and famine when they are limiting. depends on a 25kDa metalloregulatory protein, called SloR, to modulate uptake of these cations across the bacterial cell surface. When bound to manganese, SloR, binds to palindromic recognition elements in the promoter of the genes that encode the major manganese transporter in . Reports in the literature describ MntH, an ancillary manganese transporter in , that is also subject to SloR control. In the present study, we performed expression profiling experiments that reveal coordinate regulation of the and genes at the level of transcription. In addition, we describe a role for the gene product that is redundant with that of the -encoded metal ion uptake machinery. The results of DNA binding studies support direct SloR binding to the promoter region which, like that at the promoter, harbors three palindromic recognition elements to which SloR binds cooperatively to repress downstream transcription. These findings expand our understanding of the SloR metalloregulome and elucidate SloR-DNA binding that is essential for metal ion homeostasis and fitness in the oral cavity.