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Published on: November 1, 2012
Allosteric interaction of minor groove binding ligands with UL9-DNA complexes
1Genelabs Technologies, Inc., 505 Penobscot Drive, Redwood City, California 94063, USA.
Biochemistry
|October 17, 2001
Summary
Herpes simplex virus type 1 origin binding protein (UL9) interaction with DNA is disrupted by minor groove binders like GLX. This disruption occurs via allosteric inhibition, not direct competition, suggesting new gene regulation strategies.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- Herpes simplex virus type 1 origin binding protein (UL9) is a key DNA-binding protein.
- UL9 specifically recognizes and binds to the 5'-CGTTCGCACTT-3' DNA sequence, primarily through major groove interactions.
Purpose of the Study:
- To investigate the mechanism by which minor groove binding ligands disrupt the UL9-DNA complex.
- To elucidate the structural basis of UL9-DNA interaction and its modulation by ligands.
Main Methods:
- Fluorescence-based hybridization stabilization assay to determine GLX binding stoichiometry.
- Footprinting assays using 1,10-phenanthroline copper to analyze DNA conformation changes.
Main Results:
- Minor groove ligands like GLX disrupt UL9-DNA binding when overlapping the protein's binding site.
- GLX exhibits biphasic displacement, indicating two binding modes: 1:1 (preferring narrow grooves) and 2:1 (tolerating widened grooves).
- UL9-DNA complex shows a widened minor groove at the GLX binding site, suggesting allosteric inhibition by GLX at lower concentrations.
Conclusions:
- Ligand-induced displacement of UL9 is primarily mediated by allosteric inhibition due to opposing DNA conformational preferences.
- At higher concentrations, GLX can co-bind with UL9 in a widened minor groove.
- These findings offer insights into targeted gene transcription regulation strategies.
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