Characterization of total membrane protein of Porphyromonas endodontalis

Porphyromonas endodontalis strains ATCC 35406, HG 181, and HG 413 were cultured in an enriched broth medium, and growth curves were determined. Total membrane protein profiles of cells, harvested either from exponential phase or from stationary phase of growth, were studied by sodium dodecyl sulfate polyacrylamide-gel electrophoresis. The protein profiles indicated that the three strains shared three major proteins, designated A, B, and C, with molecular masses of 59, 43, and 41 kDa, respectively. In addition, the strains showed homology among the majority of the minor proteins. However, some minor proteins were unique for each strain. Two common minor proteins with molecular masses of 56 and 51 kDa were weakly expressed or absent in membrane preparations from cells of the early exponential phase, while they were present in membrane preparations from cells harvested in the late phase of growth. The major and minor membrane proteins may play a role in the interaction between P. endodontalis and the host. In addition, the membrane proteins may play an important role in the physiology of this endodontic pathogen.