[ODP-117] Molecular characteristics and the peptidoglycanase activity of Clostridium perfringens-derived autolysin, Acp
Autolysin of Clostridium perfringens (Acp, CPE1231), a single polypeptide with a molecular weight of 122 kDa, is composed of 10 N-terminal cell wall binding (CWB) domains (CWB) and a C-terminal catalytic domain (CD) which exerts an N-acethylglucosaminidase activity. In previous study, the apparent molecular weight of Acp was reported to be 95 kDa. However, the result of our experiment indicated the presence of 122 kDa Acp as well as 95 kDa Acp. Here, we investigated the expression of these Acps in the different stages of growth and their peptidoglycan-hydrolysing activity (lytic activity). In addition, the lytic activity of several recombinant Acp fragments (rAcp) were also examined. The result of Western blot analysis using anti-Acp polyclonal antibody revealed that both 122 kDa and 95 kDa were expressed during the vegetative growth, whereas only 95 kDa Acp was expressed during the stationary phase. Both 122 kDa Acp and 95 kDa Acp showed lytic activity by renaturing SDS-PAGE containing Micrococcus luteus cells. Autoclaved M. luteus cells were used for the measurement of lytic activity by various rAcps. rAcpCWB3-10+CD having 8 CWB domains and CD showed a significant higher lytic activity than that of rAcpCWB7-10+CD having 4 CWB domains and CD. These results suggest the biological significance of CWB domains in the peptidoglycanase activity of Acp.