AmpD, essential for both β-lactamase regulation and cell wall recycling, is a novel cytosolic N-acetylmuramyl-L-alanine amidase
Article first published online: 27 OCT 2006
Volume 15, Issue 3, pages 553–559, February 1995
How to Cite
Jacobs, C., Joris, B., Jamin, M., Klarsov, K., van Beeumen, J., Mengin-Lecreulx, D., van Heijenoort, J., Park, J. T., Normark, S. and Frère, J.-M. (1995), AmpD, essential for both β-lactamase regulation and cell wall recycling, is a novel cytosolic N-acetylmuramyl-L-alanine amidase. Molecular Microbiology, 15: 553–559. doi: 10.1111/j.1365-2958.1995.tb02268.x
- Issue published online: 27 OCT 2006
- Article first published online: 27 OCT 2006
- Received 9 August, 1994; accepted 17 October, 1994.
In enterobacteria, the ampD gene encodes a cytosolic protein which acts as a negative regulator of β-lactamase expression. It is shown here that the AmpD protein is a novel N-acetylmuramyl-L-alanine amidase (E.C.188.8.131.52) participating in the intracellular recycling of peptido-glycan fragments. Surprisingly, AmpD exhibits an exclusive specificity for substrates containing anhydro muramic acid. This anhydro bond is mainly found in the peptidoglycan degradation products formed by the periplasmic lytic transglycosylases and thus might behave as a‘recycling tag’allowing the enzyme to distinguish these fragments from the newly synthesized peptidoglycan precursors. The AmpD substrate (or substrates) which accumulates in the absence of the corresponding enzymatic activity acts as an intracellular positive effector for β-lactamase expression and might represent an element of a communication network between the chromosome and the cell wall peptidoglycan.