mrdA

mrdA is a bacterial gene that encodes a penicillin-binding protein involved in peptidoglycan remodeling during cell wall synthesis. The gene is commonly found in Gram-negative bacteria and is part of the MrdAB region that influences cell shape and wall integrity.

Genomic context and function: In Escherichia coli and related species, mrdA sits near mrdB, and together they contribute to the MrdAB rod-system that helps maintain rod-shaped morphology during cell elongation. The MrdA protein is a class B penicillin-binding protein with a transpeptidase domain that participates in cross-linking peptidoglycan. It acts in concert with MrdB and with other components of the broader morphogenesis network, including MreB, MreC, MreD and RodA, to coordinate cell wall synthesis with cell shape.

Phenotypes and significance: Mutations or reduced expression of mrdA can lead to alterations in cell shape, often producing wider or more spherical cells, and can influence susceptibility to beta-lactam antibiotics. The precise effects vary among species and growth conditions. The gene is a focus of study in bacterial morphogenesis and antibiotic action, particularly in model organisms such as E. coli, where it helps illuminate how the rod shape is maintained during growth and division.

Notes: The presence and function of mrdA can differ across bacterial taxa, reflecting diversity in morphogenic systems. In some organisms, its role may be partially redundant with or complemented by other penicillin-binding proteins and rod-system components.