Hinge-helix formation and DNA bending in various lac repressor-operator complexes.
EMBO J
; 18(22): 6472-80, 1999 Nov 15.
Article
in En
| MEDLINE
| ID: mdl-10562559
ABSTRACT
The hinge-region of the lac repressor plays an important role in the models for induction and DNA looping in the lac operon. When lac repressor is bound to a tight-binding symmetric operator, this region forms an alpha-helix that induces bending of the operator. The presence of the hinge-helices is questioned by previous data that suggest that the repressor does not bend the wild-type operator. We show that in the wild-type complex the hinge-helices are formed and the DNA is bent, similar to the symmetric complex. Furthermore, our data show differences in the binding of the DNA binding domains to the half-sites of the wild-type operator and reveal the role of the central base-pair of the wild-type operator in the repressor-operator interaction. The differences in binding to the operator half-sites are incorporated into a model that explains the relative affinities of the repressor for various lac operator sequences that contain left and right half-sites with different spacer lengths.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Oligodeoxyribonucleotides
/
Repressor Proteins
/
Bacterial Proteins
/
Escherichia coli Proteins
/
Lac Operon
/
Nucleic Acid Conformation
Type of study:
Prognostic_studies
Language:
En
Journal:
EMBO J
Year:
1999
Document type:
Article
Affiliation country:
Netherlands