A PEPTIDOGLYCAN BINDING DOMAIN IN THE PORIN-ASSOCIATED PROTEIN (PAP) OF RHODOSPIRILLUM-RUBRUM FR1

The porin-associated protein of Rhodospirillum rubrum FR1 was found to contain a peptidoglycan binding motif. A partial fragment of 179 amin o acids, obtained by cleavage of PAP with trypsin, Asp-N protease, and CNBr, was sequenced. Substantial sequence homology was found of the C -terminal part (residues 126-179) of porin-associated protein with Omp A, the peptidoglycan-associated lipoprotein of several bacteria, prote in F of Pseudomonas aeruginosa, and Pm of Neisseria gonorrhoeae,the la tter being also a pot-in-associated protein. The 179 amino acid fragme nt comprised about 67% of the mass spectrometrically determined total mass of PAP of 27 850 Da.