My senior work is centered on investigating the significance of two amino acid substitutions in a 25kDa SloR metalloregulatory protein, which modulates the cariogenic potential of Streptococcus mutans, an oral pathogen. Each mutation was generated via a Gibson Assembly approach, such that an asparagine at position 161 and a leucine at position 164 were converted into alanines (two non-conservative substitutions). Based on a SloR crystal structure, we hypothesize that these amino acids contribute to essential Mn2+ binding at an ancillary site within the central dimerization domain of the SloR protein. Specifically, the purpose of this investigation is to characterize the putative impact of these mutations on SloR binding to a promoter proximal DNA element at the S. mutans sIoABC locus. The effect (or lack there of) of these mutations on SloR-DNA binding could inform rational drug design aimed at alleviating and/or preventing S. mutans-induced cavities on the human dentition.
