title: The specificity requirements of bacteriophage T4 lysozyme.
abstract: A series of bacterial cell wall glycopeptides of low  molecular weight and cell wall nucleotide precursors have been tested for their inhibitory action on the digestion by T4 lysozyme of a radioactively labeled linear uncrosslinked peptidoglycan. The disaccharide-peptides GlcNAc-MurNAc-l-Ala-D-Glu(A2pm) (C5) and GlcNAc-MurNAc-L-Ala-D-Glu(A2pm-D-Ala) (C6) as well as the monosaccharide-peptide MurNAc-L-Ala-D-Glu(A2pm) were found to be good competitive inhibitors (with similar Ki values) whereas the disaccharide-pentapeptide GlcNAcMurNAc-L-Ala-DGlu-Gly-L-Lys-D-Ala was a poor inhibitor. T4 lysozyme did not catalyse transglycosylation reactions from Escherichia coli B peptidoglycan to the disaccharide-peptide C6. No changes were seen in the circular dichroism spectra (200-250 nm) or fluorescence emmission spectra upon binding of the good inhibitors. The results obtained indicate that T4 lysozyme has a small active site capable of recognizing a unit consisting of MurNAc-L-Ala-D-Glu(A2pm).
mesh_terms: D002942:Circular Dichroism; D003090:Coliphages / Q000201:enzymology*; D006020:Glycopeptides / Q000494:pharmacology; D007700:Kinetics; D008837:Micrococcus; D008970:Molecular Weight; D009113:Muramidase / Q000378:metabolism*; D010457:Peptidoglycan / Q000494:pharmacology; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D006020:Glycopeptides; D010457:Peptidoglycan; D009113:Muramidase