J. Bacteriol., Dec 1996, 7106-7111, Vol 178, No. 24
Copyright © 1996, American Society for Microbiology

dacD, an Escherichia coli gene encoding a novel penicillin-binding protein (PBP6b) with DD-carboxypeptidase activity

MR Baquero, M Bouzon, JC Quintela, JA Ayala and F Moreno
Unidad de Genetica Molecular, Hospital Ramon y Cajal, Madrid, Spain.

In the course of a study of genes located at min 44 of the Escherichia coli genome, we identified an open reading frame with the capacity to encode a 43-kDa polypeptide whose predicted amino acid sequence is strikingly similar to those of the well-known DD-carboxipeptidases penicillin-binding proteins PBP5 and PBP6. The gene product was shown to bind [3H]benzylpenicillin and to have DD-carboxypeptidase activity on pentapeptide muropeptides in vivo. Therefore, we called the protein PBP6b and the gene dacD. As with other E. coli DD-carboxypeptidases, PBP6b is not essential for cell growth. A quadruple dacA dacB dacC dacD mutant was constructed and shown to grow as well as its isogenic wild- type strain, indicating that the loss of any known PBP-associated DD- carboxypeptidase activity is not deleterious for E. coli. We also identified the homologous gene of dacD in Salmonella typhimurium as one of the components of the previously described phsBCDEF gene cluster.

This article has been cited by other articles:

• Scheffers, D.-J., Pinho, M. G. (2005). Bacterial Cell Wall Synthesis: New Insights from Localization Studies. Microbiol. Mol. Biol. Rev. 69: 585-607 [Abstract] [Full Text]  
• Ghosh, A. S., Young, K. D. (2003). Sequences near the Active Site in Chimeric Penicillin Binding Proteins 5 and 6 Affect Uniform Morphology of Escherichia coli. J. Bacteriol. 185: 2178-2186 [Abstract] [Full Text]  
• Goffin, C., Ghuysen, J.-M. (2002). Biochemistry and Comparative Genomics of SxxK Superfamily Acyltransferases Offer a Clue to the Mycobacterial Paradox: Presence of Penicillin-Susceptible Target Proteins versus Lack of Efficiency of Penicillin as Therapeutic Agent. Microbiol. Mol. Biol. Rev. 66: 702-738 [Abstract] [Full Text]  
• Nelson, D. E., Ghosh, A. S., Paulson, A. L., Young, K. D. (2002). Contribution of Membrane-Binding and Enzymatic Domains of Penicillin Binding Protein 5 to Maintenance of Uniform Cellular Morphology of Escherichia coli. J. Bacteriol. 184: 3630-3639 [Abstract] [Full Text]  
• Nelson, D. E., Young, K. D. (2001). Contributions of PBP 5 and DD-Carboxypeptidase Penicillin Binding Proteins to Maintenance of Cell Shape in Escherichia coli. J. Bacteriol. 183: 3055-3064 [Abstract] [Full Text]  
• Lázaro, S., Fernández-Piñas, F., Fernández-Valiente, E., Blanco-Rivero, A., Leganés, F. (2001). pbpB, a Gene Coding for a Putative Penicillin-Binding Protein, Is Required for Aerobic Nitrogen Fixation in the Cyanobacterium Anabaena sp. Strain PCC7120. J. Bacteriol. 183: 628-636 [Abstract] [Full Text]  
• Nelson, D. E., Young, K. D. (2000). Penicillin Binding Protein 5 Affects Cell Diameter, Contour, and Morphology of Escherichia coli. J. Bacteriol. 182: 1714-1721 [Abstract] [Full Text]  
• Pfeifle, D., Janas, E., Wiedemann, B. (2000). Role of Penicillin-Binding Proteins in the Initiation of the AmpC beta -Lactamase Expression in Enterobacter cloacae. Antimicrob. Agents Chemother. 44: 169-172 [Abstract] [Full Text]  
• Denome, S. A., Elf, P. K., Henderson, T. A., Nelson, D. E., Young, K. D. (1999). Escherichia coli Mutants Lacking All Possible Combinations of Eight Penicillin Binding Proteins: Viability, Characteristics, and Implications for Peptidoglycan Synthesis. J. Bacteriol. 181: 3981-3993 [Abstract] [Full Text]  
• Berlyn, M. K. B. (1998). Linkage Map of Escherichia coli K-12, Edition 10: The Traditional Map. Microbiol. Mol. Biol. Rev. 62: 814-984 [Abstract] [Full Text]  
• Murray, T., Popham, D. L., Setlow, P. (1998). Bacillus subtilis Cells Lacking Penicillin-Binding Protein 1 Require Increased Levels of Divalent Cations for Growth. J. Bacteriol. 180: 4555-4563 [Abstract] [Full Text]  
• Holtje, J.-V. (1998). Growth of the Stress-Bearing and Shape-Maintaining Murein Sacculus of Escherichia coli. Microbiol. Mol. Biol. Rev. 62: 181-203 [Abstract] [Full Text]