Lipid modification of Escherichia coli penicillin-binding protein 3

The primary structure of penicillin-binding protein 3 (PBP 3), an essential enzyme for cell division in Escherichia coli, was deduced from the nucleotide sequence of the ftsI gene (M. Nakamura, I. N. Maruyama, M. Soma, J. Kato, H. Suzuki, and Y. Hirota, Mol. Gen. Genet. 191:1-9, 1983). An amino acid sequence of Leu-26-Leu-Cys-Gly-Cys-30 was found near the amino terminus of the deduced sequence, showing a rather striking homology to the Leu-Leu-Ala-Gly-Cys consensus sequence for the modification and processing of precursors of the E. coli murein lipoprotein and other bacterial lipoproteins. As expected from this finding, PBP 3 was found to be modified with glycerol and fatty acids, although the lipid modification occurred only in a small fraction, accounting for less than 15% of the total PBP 3 molecules.