Immunolocalization of Secretion complex in Streptococcus mutans

Objective To investigate the distribution pattern of the Secretion complex in Streptococcus mutans by means of the subcellular localization of SecA and SecY.Methods The specificity of anti-SecA antibody and the anti-SecY antibody were examined by Western blot.An indirect post- embedding immunogold method was used to determine the subcellular localization of the SecA and SecY in the cytoplasmic membrane of the Streptococcus mutans GS-5.Results Immunoblotting results showed that the anti-SecA antibody and the anti-SecY antibody specifically recognized a single band of about 95 000 and 47 800 respectively.Immunogold electron microscopy revealed a single intense focus of gold particles at a discrete location on the cytoplasmic membrane of the Streptococcus mutans GS-5.Conclusions SecA and SecY clustered to an asymmetric microdomain,which suggests that Sec complex present a uni-site on the cytoplasmic membrane of Streptococcus mutans.