Solid-state 15N NMR studies of the effects of penicillin on cell-wall metabolism of Aerococcus viridans (Gaffkya homari).

Lyophilized whole cells and isolated cell walls from Aerococcus viridans (Gaffkya homari) grown on a synthetic medium containing benzylpenicillin, and either L-[epsilon-15N]lysine or 15N-ammonium ion as the only source of label, have been studied using cross-polarization magic-angle spinning 15N nuclear magnetic resonance. The lysine is incorporated directly into protein and cell-wall peptidoglycan and was used to measure cell-wall cross-links. The ammonium ion acts as a non-specific label monitoring general metabolism. Inhibition of cell-wall cross linking by penicillin occurs, but may not be the exclusive cause of cell death and lysis in this microorganism. Instead, the disruption of the mechanism for control of peptidoglycan synthesis probably is a contributing factor.