RESUMEN
The ampG gene codes for a permease required to uptake anhydro-muropeptides into bacterial cytoplasm. Located upstream in the same operon, is another 579-base-pair-long open reading frame encoding a putative lipoprotein YajG, whose nearly complete 1H,13C,15N assignments are reported here.
Asunto(s)
Proteínas de Escherichia coli/química , Secuencia de Bases , Cartilla de ADN/genética , ADN Bacteriano/genética , Proteínas de Escherichia coli/genética , Lipoproteínas/química , Lipoproteínas/genética , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Proteínas Recombinantes/química , Proteínas Recombinantes/genéticaRESUMEN
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.