Open AccessAn Alternative Route for Recycling of N -Acetylglucosamine from Peptidoglycan Involves the N -Acetylglucosamine Phosphotransferase System in Escherichia coli
Author(s) -
Jacqueline Plumbridge
Publication year - 2009
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.00448-09
Subject(s) - pep group translocation , peptidoglycan , n acetylglucosamine , biology , escherichia coli , biochemistry , phosphotransferase , enzyme , acetylglucosamine , mutation , mutant , microbiology and biotechnology , gene
A set of enzymes dedicated to recycling of the amino sugar components of peptidoglycan has previously been identified inEscherichia coli . The complete pathway includes thenagA -encoded enzyme,N -acetylglucosamine-6-phosphate (GlcNAc6P) deacetylase, of the catabolic pathway for use ofN -acetylglucosamine (GlcNAc). Mutations innagA result in accumulation of millimolar concentrations of GlcNAc6P, presumably by preventing peptidoglycan recycling. Mutations in the genes encoding the key enzymes upstream ofnagA in the dedicated recycling pathway (ampG ,nagZ ,nagK ,murQ , andanmK ), which were expected to interrupt the recycling process, reduced but did not eliminate accumulation of GlcNAc6P. A mutation in thenagE gene of the GlcNAc phosphotransferase system (PTS) was found to reduce by 50% the amount of GlcNAc6P which accumulated in anagA strain and, together with mutations in the dedicated recycling pathway, eliminated all the GlcNAc6P accumulation. This shows that then agE -encoded PTS transporter makes an important contribution to the recycling of peptidoglycan. ThemanXYZ -encoded PTS transporter makes a minor contribution to the formation of cytoplasmic GlcNAc6P but appears to have a more important role in secretion of GlcNAc and/or GlcNAc6P from the cytoplasm.