Open AccessMembrane Topology of the Escherichia coli AmpG Permease Required for Recycling of Cell Wall Anhydromuropeptides and AmpC β-Lactamase Induction
Author(s) -
Aicha Chahboune,
Marc Decaffmeyer,
Robert Brasseur,
Bernard Joris
Publication year - 2005
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.49.3.1145-1149.2005
Subject(s) - periplasmic space , peptidoglycan , escherichia coli , permease , cytoplasm , biology , biochemistry , bacterial outer membrane , transmembrane protein , inner membrane , bacterial cell structure , bacteria , membrane topology , cell wall , cell envelope , membrane protein , membrane , gene , genetics , receptor
Escherichia coli, and presumably most other gram-negative bacteria, possesses an efficient protein machinery for recycling its peptidoglycan during cell growth. The major recycled peptidoglycan product is N-acetylglucosamine-1,6-anhydro-N-acetylmuramic acid-tetrapeptide. Its uptake from the periplasm into the cytoplasm is carried out via the AmpG protein, an intrinsic membrane protein. In gram-negative bacteria carrying an ampC beta-lactamase-inducible gene on their chromosomes, the induction mechanism is directly linked to peptidoglycan recycling. After identification of the different putative hydrophobic segments by computing, the AmpG topology was experimentally determined by using beta-lactamase fusion. In the proposed model, AmpG contains 10 transmembrane segments and two large cytoplasmic loops.