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Dimerization allows DNA target site recognition by the NarL response regulator.
Ann E Maris1, Michael R Sawaya, Maria Kaczor-Grzeskowiak
1Department of Chemistry and Biochemistry, University of California, Los Angeles, P.O. Box 951569, Los Angeles, California 90095-1569, USA.
Nature Structural Biology
|September 28, 2002
Summary
The study reveals how Escherichia coli NarL proteins bind DNA using a novel dimerization interface and subtle forces like solvation and van der Waals interactions. This binding induces significant DNA curvature and a B- to A-form DNA transition.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Two-component signal transduction systems are crucial regulatory pathways in prokaryotes.
- The NarL protein is a key response regulator in Escherichia coli's two-component system.
- Understanding DNA-binding mechanisms is vital for deciphering gene regulation.
Purpose of the Study:
- To elucidate the structural basis of DNA recognition by the NarL response regulator.
- To investigate the role of protein-DNA interactions in modulating DNA structure.
- To characterize the molecular mechanisms underlying NarL-mediated gene regulation.
Main Methods:
- Co-crystal structure determination of Escherichia coli NarL signal output domain bound to DNA.
- Analysis of protein-DNA interfaces and interactions.
- Examination of DNA structural changes upon NarL binding.
Main Results:
- A novel dimerization interface is formed upon NarL binding to DNA.
- DNA recognition is mediated by solvation, van der Waals forces, and DNA deformability, not solely major groove hydrogen bonding.
- NarL binding induces significant DNA curvature and a transition from B- to A-form DNA.
- Unexpected interaction observed between valine and the polar major groove floor.
Conclusions:
- NarL utilizes a unique mechanism involving domain rearrangement and subtle forces for DNA binding.
- The observed DNA structural changes are critical for NarL's regulatory function.
- This study provides atomic-level insights into two-component system-mediated gene regulation.