Cross-linking and O-acetylation of newly synthesized peptidoglycan in Staphylococcus aureus H.
Staphylococcus aureus H growing exponentially was labelled with N-acetyl[14C]glucosamine, which became incorporated into the peptidoglycan. The portion of peptidoglycan not linked to teichoic acid (60-75% of the whole) was degraded with Chalaropsis muramidase to yield disaccharide-peptide monomers and dimers, trimers and oligomers formed by biosynthetic cross-linking of the monomers. The degree of O-acetylation of these fragments was also examined. Pulse-chase experiments showed that the proportion of label initially in the monomer fraction immediately after the 1 min pulse declined rapidly during a 3 min chase, while the oligomer fraction (fragments greater than trimer) gained the radioactivity proportionately. The radioactivity of the dimer and trimer fractions remained virtually unchanged. At 4 min after the commencement of labelling (i.e. approx. one-tenth of a generation time) final values had been reached. The O-acetylation of all fragments had achieved final values even at 1 min, except for the monomer fraction, which showed an increase from 40% to 60% during the first 3 min of chase. Although O-acetylation was clearly a very rapid process, no O-acetylated peptidoglycan lipid-intermediates could be detected.
Snowden
M A
MA
Department of Genetics and Microbiology, University of Liverpool, UK.
Perkins
H R
HR
Wyke
A W
AW
Hayes
M V
MV
Ward
J B
JB
D000107:Acetylation; D002236:Carbohydrate Conformation; D050356:Lipid Metabolism; D010457:Peptidoglycan / Q000096:biosynthesis*; D013211:Staphylococcus aureus / Q000378:metabolism*
D010457:Peptidoglycan