PDBsum entry 2p7c

Transcription regulator

PDB id: 2p7c

Contents

Protein chain

82 a.a. *

DNA/RNA

* Residue conservation analysis

PDB id:

2p7c

Name:

Transcription regulator

Title:

Solution structure of the bacillus licheniformis blai monomeric form in complex with the blap half-operator.

Structure:

Strand 1 of twelve base-pair DNA. Chain: a. Engineered: yes. Strand 2 of twelve base-pair DNA. Chain: c. Engineered: yes. Penicillinase repressor. Chain: b. Fragment: n-terminal domain.

Source:

Synthetic: yes. Other_details: chemically synthetized bacillus licheniformis blap half-operator. Bacillus licheniformis. Organism_taxid: 1402. Strain: bacillus licheniformis 749/i. Gene: blai, peni. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

10 models

Authors:

J.Boudet,V.Duval,H.Van Melckebeke,M.Blackledge,A.Amoroso,B.Joris,J.- P.Simorre

Key ref:

J.Boudet et al. (2007). 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. Nucleic Acids Res, 35, 4384-4395. PubMed id: 17576674

Date:

20-Mar-07 Release date: 12-Jun-07

Protein chain

P06555  (BLAI_BACLI) -  Penicillinase repressor from Bacillus licheniformis

Seq: 128 a.a.

Struc: 82 a.a.

DNA/RNA chains

A-A-A-G-T-A-T-T-A-C-A-T 12 bases

A-T-G-T-A-A-T-A-C-T-T-T 12 bases

Enzyme reactions

• Enzyme class: E.C.?

Nucleic Acids Res 35:4384-4395 (2007)

PubMed id: 17576674

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.

J.Boudet, V.Duval, H.Van Melckebeke, M.Blackledge, A.Amoroso, B.Joris, J.P.Simorre.

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 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.