Induction of β-lactamase and low-affinity penicillin binding protein 2' synthesis in gram-positive bacteria

This chapter discusses the induction of β-lactamase and low-affinity penicillin binding protein 2' synthesis in Gram-positive bacteria. Resistance to β-lactam antibiotics can be β-lactamase-and/or penicillin-binding protein (PBP)-mediated. This chapter presents a review on the molecular mechanisms by which a β-lactam compound can induce β-lactamase synthesis in Bacillus lichenformis and both β-lactamase and low-affinity PBP2' synthesis in staphylococcus aureus. The mechanisms differ markedly from those responsible for chromosomal β-lactamase induction in Gram-negative bacteria. Regulation of β-lactamase and PBP2' synthesis is at the transcriptional level. Many bacterial repressors are dimeric molecules that recognize specific palindromic sequences of the DNA helix. The significance of the palindromic nature of these sequences is that the two DNA binding sites are related by an approximate twofold symmetry axis and that each subunit of the dimeric repressor has a helix-turn-helix (HTH) motif whose second (recognition) helix interacts at the major groove of the DNA in its B-form.
Copyright © 1994 Published by Elsevier B.V.