2p7c | pdb_00002p7c

Solution structure of the bacillus licheniformis BlaI monomeric form in complex with the blaP half-operator.

spinqualitylabelsall models 2p7c, 10 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2p7c is a 3 chain structure with sequence from Bacillus licheniformis. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: blaI, penI (Bacillus licheniformis) Resources: FirstGlance, OCA, RCSB, PDBsum Function [BLAI_BACLI] Transcriptional repressor that constitutively blocks expression of beta-lactamase. Regulates genes involved in antibiotic resistance. Binds DNA as a dimer. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed 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 repressor complexed to the semi-operating sequence OP1 of blaP (1/2OP1blaP) by using a de novo docking approach based on inter-molecular nuclear Overhauser effects and chemical-shift differences measured on each macromolecular partner. Although the N-terminal domain of the repressor is not subject to internal structural rearrangements upon DNA binding, the molecules adopt a tertiary conformation different from the crystallographic operator-repressor dimer complex, leading to a 30 degrees rotation of the monomer with respect to a central axis extended across the DNA. These results open new insights for the repression and induction mechanisms of bacterial resistance to beta-lactams. 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.,Boudet J, Duval V, Van Melckebeke H, Blackledge M, Amoroso A, Joris B, Simorre JP Nucleic Acids Res. 2007;35(13):4384-95. Epub 2007 Jun 18. PMID:17576674 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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