Back to Search
Start Over
Mutual stabilisation of bacteriophage Mu repressor and histone-like proteins in a nucleoprotein structure.
- Source :
-
Journal of molecular biology [J Mol Biol] 1995 Jun 02; Vol. 249 (2), pp. 332-41. - Publication Year :
- 1995
-
Abstract
- Integration host factor (IHF) binds in a sequence-specific manner to the bacteriophage Mu early operator. It participates with bound Mu repressor, c, in building stable, large molecular mass nucleoprotein complexes in vitro and enhances repression of early transcription in vivo. We demonstrate that, when the specific IHF binding site with the operator is mutated, the appearance of large molecular mass complexes still depends on IHF and c, but the efficiency of their formation is reduced. Moreover, the IHF-like HU protein, which binds DNA in a non-sequence-specific way, can substitute for IHF and participate in complex formation. Since the complexes require both c and a host factor (IHF or HU), the results imply that these proteins stabilise each other within the nucleoprotein structures. These results suggest that IHF and HU are directed to the repressor-operator complexes, even in the absence of detectable sequence-specific binding. This could be a consequence of their preferential recognition of DNA containing a distortion such as that introduced by repressor binding to the operator. The histone-like proteins could then stabilise the nucleoprotein complexes simply by their capacity to maintain a bend in DNA rather than by specific protein-protein interactions with c. This model is supported by the observation that the unrelated eukaryotic HMG-1 protein, which exhibits a similar marked preference for structurally deformed DNA, is also able to participate in the formation of higher-order complexes with c and the operator DNA.
- Subjects :
- Animals
Bacterial Proteins chemistry
Bacteriophage mu genetics
Base Sequence
Binding Sites
Consensus Sequence
DNA Primers
DNA, Viral chemistry
DNA, Viral metabolism
DNA-Binding Proteins chemistry
Deoxyribonuclease I
Electrophoresis, Polyacrylamide Gel
High Mobility Group Proteins chemistry
Histones metabolism
Integration Host Factors
Kinetics
Models, Structural
Molecular Sequence Data
Mutagenesis, Site-Directed
Nucleic Acid Conformation
Polymerase Chain Reaction
Protein Conformation
Rats
Recombinant Proteins chemistry
Recombinant Proteins metabolism
Repressor Proteins chemistry
Substrate Specificity
Bacterial Proteins metabolism
Bacteriophage mu metabolism
DNA-Binding Proteins metabolism
Escherichia coli metabolism
High Mobility Group Proteins metabolism
Nucleoproteins chemistry
Plasmids
Repressor Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0022-2836
- Volume :
- 249
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Journal of molecular biology
- Publication Type :
- Academic Journal
- Accession number :
- 7783197
- Full Text :
- https://doi.org/10.1006/jmbi.1995.0300