Streptococus mutans is known as a primary pathogen of dental caries, which experiences all kinds of pressure changes in oral cavity, and its pathogenicity closely relates to the tolerance in a variety of environments. The spx protein is a global regulator in Gram-positive bacteria, and plays a particular role in stress tolerance, survival and virulence of Streptococus mutans. This article reviewed the spx protein, the structure of spx/α-C terminal domain complex and the regulation of spx protein in Streptococus mutans and non-cariogenic bacterias.
