PT - JOURNAL ARTICLE AU - AMRAM SAMUNI AU - AMATZYA Y. MEYER TI - Conformation Patterns in Penicillins and the Penicillin-Penicillinase Interaction DP - 1978 Jul 01 TA - Molecular Pharmacology PG - 704--709 VI - 14 IP - 4 4099 - http://molpharm.aspetjournals.org/content/14/4/704.short 4100 - http://molpharm.aspetjournals.org/content/14/4/704.full SO - Mol Pharmacol1978 Jul 01; 14 AB - Conformational energy maps have been computed for three penicillin derivatives by the quantum mechanical method of perturbative configuration interaction using localized orbitals (PCILO). It was found that rotation about the C—N bond to the acyl side chain is quite hindered, with a preferred conformation that is practically independent of the side chain. However, the energetics of rotation about axes in the side chain depend greatly on its structure. The computed patterns permit two types of penicillin derivatives to be distinguished. This differentiation is parallel to the experimental classification of penicillins as S- or A-type by the mode of their interaction with penicillinase. An interpretation of this parallelism is proposed.