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Nuclear magnetic resonance-based model of a TF1/HmU-DNA complex
M V Silva1, L B Pasternack, D R Kearns
1Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla 92093, USA.
Archives of Biochemistry and Biophysics
|January 22, 1998
Summary
Bacillus subtilis bacteriophage SPO1 transcription factor 1 (TF1) binds DNA containing 5-hydroxymethyl-2'-deoxyuridine (HmU). NMR studies reveal TF1
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Transcription factor 1 (TF1) is a type II DNA-binding protein from Bacillus subtilis bacteriophage SPO1.
- TF1 exhibits sequence-selective DNA binding, with a known preference for 5-hydroxymethyl-2 kinter-deoxyuridine (HmU)-containing DNA.
Purpose of the Study:
- To elucidate the DNA-binding mechanism of TF1.
- To characterize the structural interactions between TF1 and HmU-containing DNA.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy was employed to study the TF1/HmU-DNA complex.
- Intermolecular and intramolecular Nuclear Overhauser Effects (NOEs) were analyzed.
- An energy-minimized model of the protein-DNA complex was generated.
Main Results:
- NMR data indicated that the flexible beta-ribbon and C-terminal alpha-helix of TF1 constitute the DNA-binding site.
- These findings place TF1 within the beta-sheet category of DNA-binding proteins.
- The model revealed significant DNA bending and protein structure alterations upon complex formation.
Conclusions:
- TF1 likely binds DNA by wrapping its beta-ribbon "arms" around the molecule.
- The study provides insights into the structural basis of TF1's DNA recognition and binding.
- The observed DNA bending and protein conformational changes highlight the dynamic nature of protein-DNA interactions.