Interactions between Divalent Cations and a Periplasmic Lipoprotein involved in Salmonella Magnesium Homeostasis

Abstract

All living cells require magnesium to generate biochemical energy during metabolism and for maintenance of essential structures. A recently discovered protein of unknown function, DcrB, plays a role in magnesium homeostasis within Salmonella enterica, which must adapt to low external levels of Mg2+ to cause food‐borne illness. DcrB is a small protein attached to the periplasmic face of the cytoplasmic membrane. Given this location, one possible model for the function of DcrB is that DcrB brings Mg2+ to membrane Mg2+ transporters in the cytoplasmic membrane. Currently, Salmonella phenotypic assays have shown DcrB to promote growth in low Mg2+. The hypothesis of this project is that DcrB binds magnesium and possibly other divalent cations. To test this hypothesis, we examined whether Mg2+ and other divalent cations affected the thermal stability of purified DcrB protein. We examined the effect of divalent cations using a fluorescence‐based thermal shift assay and circular dichroism techniques. Furthermore, we are using our recent crystallographic structure of DcrB to identify and test specific metal binding sites. Our results have established the specificity of DcrB for binding divalent cations, which we anticipate will shed light on the role of DcrB in metal homeostasis in pathogenic bacteria.Support or Funding InformationThis research is supported by a University of Wisconsin‐‐La Crosse Undergraduate Research and Creativity Grant (RS) and a University of Wisconsin‐‐La Crosse Faculty Research Grant (JM).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.