Moderate deacylation efficiency of DacD explains its ability to partially restore beta-lactam resistance in Escherichia coli PBP5 mutant.

Chiranjit Chowdhury, Debasish Kar, Mouparna Dutta, Akash Kumar, Anindya S Ghosh

Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal, India.

FEMS microbiology letters 2012 Dec

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Of the five dd-carboxypeptidases in Escherichia coli, only PBP5 demonstrates its physiological significance by maintaining cell shape and intrinsic beta-lactam resistance. DacD can partially compensate for the lost beta-lactam resistance in PBP5 mutant, although its biochemical reason is unclear. To understand the mechanism(s) underlying such behaviour, we constructed soluble DacD (sDacD) and compared its biophysical and biochemical properties with those of sPBP5, in vitro. Unlike sPBP6, sDacD can deacylate Bocillin significantly, which is very similar to sPBP5. sDacD shows weak dd-carboxypeptidase activity, although lower than that of sPBP5. Bioinformatics analyses reveal a similar architecture of sPBP5 and sDacD. Therefore, based on the obtained results we can infer that biochemically DacD and PBP5 are more closely related to each other than to PBP6, enabling DacD and PBP5 to play a nearly similar physiological function in terms of recovering the lost beta-lactam resistance. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Citation

Chiranjit Chowdhury, Debasish Kar, Mouparna Dutta, Akash Kumar, Anindya S Ghosh. Moderate deacylation efficiency of DacD explains its ability to partially restore beta-lactam resistance in Escherichia coli PBP5 mutant. FEMS microbiology letters. 2012 Dec;337(1):73-80