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ATP-mediated changes in cross-subunit interactions in the RecA protein
K M Logan1, A L Forget, J P Verderese
1Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655-0103, USA.
Biochemistry
|September 19, 2001
Summary
RecA protein undergoes conformational changes upon ATP and DNA binding. Specific cross-subunit interactions in the RecA protein interface differ between free RecA and RecA/ATP/DNA filaments.
Area of Science:
- Molecular biology
- Protein structure and function
- Biochemistry
Background:
- RecA protein is crucial for DNA repair and recombination.
- RecA undergoes significant conformational changes upon binding ATP and DNA.
- Previous studies implicated residues K6 and R28 in RecA oligomer stabilization.
Purpose of the Study:
- To investigate the role of specific cross-subunit interactions in RecA protein structure.
- To determine how ATP and DNA binding affect these interactions.
- To compare RecA protein structure in free versus nucleoprotein filament states.
Main Methods:
- Site-directed mutagenesis to introduce cysteine substitutions.
- Disulfide bond formation assays to probe cross-subunit interactions.
- Biochemical analysis of RecA protein filaments.
Main Results:
- Engineered cysteine substitutions allowed for disulfide bond formation.
- The efficiency of disulfide bond formation varied with ATP and DNA presence.
- These changes suggest altered cross-subunit contacts in RecA/ATP/DNA filaments compared to free RecA.
Conclusions:
- Specific cross-subunit interactions within the RecA interface are modulated by ATP and DNA.
- These findings support a model where RecA protein undergoes structural rearrangements upon filament formation.
- The study provides insights into the dynamic nature of RecA protein during DNA processing.