Proteome analysis of the Chlamydia pneumoniae elementary body

Chlamydia pneumoniae is an obligate intracellular human pathogen that cause s acute and chronic respiratory tract diseases and that has been implicated as a possible risk factor in the development of atherosclerotic heart dise ase. C. pneumoniae cultivated in Hep-2 cells were S-35-labeled and infectio us elementary bodies (EB) were purified. The EB proteins were separated by two-dimensional gel electrophoresis. Excised protein spots were in-gel dige sted with trypsin and peptides were concentrated on reverse-phase chromatog raphic beads for identification analysis by matrix-assisted laser desorptio n/ionization-mass spectrometry. In the pH range from 3-11, 263 C. pneumonia e protein spots encoded from 167 genes were identified. These genes constit ute 15% of the genome. The identified proteins include 31 hypothetical prot eins. It has recently been suggested that EB should be able to synthesize A TP. This view may be strengthened by the identification of several proteins involved in energy metabolism. Furthermore, proteins have been found which are involved in the type III secretion apparatus important for pathogenesi s of intracellular bacteria. Proteome maps and a table of all identified pr oteins have been made available on the world wide web at www.gram.au.dk.