Conformational and thermodynamic changes of the repressor/DNA operator complex upon monomerization shed new light on regulation mechanisms of bacterial resistance against beta-lactam antibiotics.

ABSTRACT: In absence of beta-lactam antibiotics, BlaI and MecI homodimeric repressors negatively control the expression of genes involved in beta-lactam resistance in Bacillus licheniformis and in Staphylococcus aureus. Subsequently to beta-lactam presence, BlaI/MecI is inactivated by a single-point proteolysis that separates its N-terminal DNA-binding domain to its C-terminal domain responsible for its dimerization. Concomitantly to this proteolysis, the truncated repressor acquires a low affinity for its DNA target that explains the expression of the structural gene for resistance. To understand the loss of the high DNA affinity of the truncated repressor, we have determined the different dissociation constants of the system and solved the solution structure of the B. licheniformis monomeric repre

SUBMITTER: Boudet J 

PROVIDER: S-EPMC1935004 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature