PDBsum entry: 1cjg

Transcription/DNA

PDB id: 1cjg

Contents

Protein chains

62 a.a. *

DNA/RNA

* Residue conservation analysis

PDB id:

1cjg

Name:

Transcription/DNA

Title:

Nmr structure of lac repressor hp62-DNA complex

Structure:

Protein (lac repressor). Chain: a, b. Fragment: headpiece, residues 1 - 62. Synonym: lac hp62. Engineered: yes. Other_details: the protein contains the 62 n-terminal residues (i.E., The DNA binding region) of the complete lac repressor protein. DNA (5'-

Source:

Escherichia coli. Organism_taxid: 562. Gene: lac i, the part encoding the 62 n-terminal aminoacids. Expressed in: escherichia coli. Expression_system_taxid: 562. Pet-hp62. Synthetic: yes. Other_details: the fragment is a variant of the wild-type

NMR struc:

11 models

Authors:

C.A.E.M.Spronk,A.M.J.J.Bonvin,P.K.Radha,G.Melacini, R.Boelens,R.Kaptein

Key ref:

C.A.Spronk et al. (1999). The solution structure of Lac repressor headpiece 62 complexed to a symmetrical lac operator. Structure, 7, 1483-1492. PubMed id: 10647179 DOI: 10.1016/S0969-2126(00)88339-2

Date:

14-Apr-99 Release date: 01-Jan-00

Protein chains

P03023  (LACI_ECOLI) -  Lactose operon repressor

Seq: 360 a.a.

Struc: 62 a.a.

 Gene Ontology (GO) functional annotation 

• Cellular component: intracellular (1 term)
• Biological process: regulation of transcription, DNA-dependent (1 term)
• Biochemical function: DNA binding (2 terms)

DOI no: 10.1016/S0969-2126(00)88339-2

Structure 7:1483-1492 (1999)

PubMed id: 10647179

The solution structure of Lac repressor headpiece 62 complexed to a symmetrical lac operator.

C.A.Spronk, A.M.Bonvin, P.K.Radha, G.Melacini, R.Boelens, R.Kaptein.

ABSTRACT

BACKGROUND: Lactose repressor protein (Lac) controls the expression of the lactose metabolic genes in Escherichia coli by binding to an operator sequence in the promoter of the lac operon. Binding of inducer molecules to the Lac core domain induces changes in tertiary structure that are propagated to the DNA-binding domain through the connecting hinge region, thereby reducing the affinity for the operator. Protein-protein and protein-DNA interactions involving the hinge region play a crucial role in the allosteric changes occurring upon induction, but have not, as yet, been analyzed in atomic detail. RESULTS: We have used nuclear magnetic resonance (NMR) spectroscopy and restrained molecular dynamics (rMD) to determine the structure of the Lac repressor DNA-binding domain (headpeice 62; HP62) in complex with a symmetrized lac operator. Analysis of the structures reveals specific interactions between Lac repressor and DNA that were not found in previously investigated Lac repressor-DNA complexes. Important differences with the previously reported structures of the HP56-DNA complex were found in the loop following the helix-turn-helix (HTH) motif. The protein-protein and protein-DNA interactions involving the hinge region and the deformations in the DNA structure could be delineated in atomic detail. The structures were also used for comparison with the available crystallographic data on the Lac and Pur repressor-DNA complexes. CONCLUSIONS: The structures of the HP62-DNA complex provide the basis for a better understanding of the specific recognition in the Lac repressor-operator complex. In addition, the structural features of the hinge region provide detailed insight into the protein-protein and protein-DNA interactions responsible for the high affinity of the repressor for operator DNA.

Selected figure(s)

Figure 1.
Figure 1. Ensemble of NMR structures of the HP62-DNA complex. (a) Backbone trace of the full HP62-DNA complex. Numbers indicate the residues of HP62. The DNA backbone is shown as a ribbon. (b) Overlay of the 11 final structures of the HP62-DNA complex. Superimposed are all atoms of residues 4-25, 32-58 of both HP62 monomers (red) and the central 18 base pairs of the lac operator (blue). Residues 4-59 of the two monomers and the full lac operator sequence are shown. (c) View perpendicular to (b). This figure was generated using the program Biosym Insightll.

The above figure is reprinted by permission from Cell Press: Structure (1999, 7, 1483-1492) copyright 1999.

Figure was selected by the author.