Polymerization by transglycosylation in the biosynthesis of the peptidoglycan of Escherichia coli K 12 and its inhibition by antibiotics

The Lantibiotic NAI-107 Binds to Bactoprenol-bound Cell Wall Precursors and Impairs Membrane Functions

“…In staphylococci, the peptidyltransferases FemXAB catalyze the attachment of a pentaglycine-interpeptide bridge (13,14) and the glutamate in position 2 of the stempeptide is amidated to glutamine by the bienzyme complex MurT-GatD (15). The fully modified lipid II molecule is then translocated across the cytoplasmic membrane (16) where it is assembled into the growing peptidoglycan network through the activity of transglycosylases and transpeptidases (penicillinbinding protein (PBPs)), thereby releasing the C 55 P-carrier, which after dephosphorylation enters a new synthesis cycle. Binding of nisin to lipid II locks the cell wall precursor in a stable complex, thereby blocking the entire peptidoglycan synthesis cycle.…”

“…The compound was discovered during a screening program designed to detect all classes of cell-wall inhibitors except for ␤-lactams and glycopeptides (4). In addition to one methyllanthionine and three lanthionine bridges and a C-terminal S-((Z)-2-aminovinyl)-D-cysteine, modifications found in other lantibiotics, NAI-107 contains two unusually modified amino acids: 5-chlorotryptophan and 3,4-dihydroxyproline (16,25). These modifications are unique to NAI-107 within the lantibiotic class of compounds and are rare in other ribosomally synthesized peptides.…”

Biosynthesis of the peptidoglycan of Escherichia coli K‐12

“…Experiments were carried out with particulate fractions prepared as [2] When the in vitro trans~yco~lation reaction was performed with particulate fractions from E. coli K-12 in the absence of any penicillin, the lipid intermediate was rapidly degraded, only low amounts of polymerized material were formed &d -50% of the ['4C]alanine of the substrate was released (table 1). In E. coli different penicillin-sensitive D-alanine carboxypeptidase activities, which catalyse the release mM Mg Cl, .…”

“…In E. coli different penicillin-sensitive D-alanine carboxypeptidase activities, which catalyse the release mM Mg Cl, . The reaction products were separated and quantified as in [2]. Activities are expressed as the % of the radioactivity in the polymerized material to that in the polymerized material and in the remaining lipid intermediate.…”

Characterization of derivatives of the high-molecular-mass penicillin-binding protein (PBP) 1 of Mycobacterium leprae

“…These can be further divided into two groups based on sequence similarity searches [3,4]. The high-molecular-mass PBPs of class A are bifunctional enzymes that catalyse both the polymerization of the glycan chains (transglycosylation) and the cross-linking of the peptide chains (transpeptidation) during cell wall synthesis [5][6][7][8][9][10]. The transglycosylation function rests within the N-terminal n-PB module, while the transpeptidation function rests within the C-terminal PB module [11].…”