Investigations into the Activity of the Novel Protein Syn-fes2

Abstract

The Hecht laboratory has previously found de novo proteins which rescue auxotrophic E. coli single-deletion strains. One of these novel proteins, syn-fes2, is the subject of further investigation herein. Syn-fes2 rescues the Δfes strain of E. coli, which has a deletion for a key protein in the iron acquisition pathway. Under certain conditions, rescue by syn-fes2 turns the cells red. The effect of growth conditions and novel protein expression on cell color is examined, as well as the potential for ferric enterobactin, the substrate of the natural protein, to cause this color. Syn-fes2 expression was found to have a significant effect upon cell color and that it was due to ferric enterobactin. Enzymatic activity and binding of syn-fes2 to ferric enterobactin were not discovered, but binding to iron was found. This suggests a possibility for syn-fes2 to operate via a cofactor that has not yet been tested or via a novel bypass pathway. In particular, one experiment provided strong indications that syn-fes2 rescue involves changes in ferric enterobactin transport. Though the specifics of the syn-fes2 iron acquisition pathway are not fully determined, it is clear that syn-fes2 and ferric enterobactin play key roles.