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Three-dimensional dimer structure of the lambda-Cro repressor in solution as determined by heteronuclear
H Matsuo1, M Shirakawa, Y Kyogoku
1Institute for Protein Research, Osaka University, Japan.
Journal of Molecular Biology
|December 8, 1995
Summary
This study fully assigned magnetic resonances for lambda-Cro repressor using NMR, revealing its 3D solution structure. The dimer structure in solution differs from the crystal form, suggesting DNA binding-induced distortion.
Area of Science:
- Structural Biology
- Biophysics
- Molecular Biology
Background:
- The lambda-Cro repressor is a key protein in bacteriophage lambda genetic regulation.
- Understanding its three-dimensional structure is crucial for elucidating its DNA-binding mechanism.
Purpose of the Study:
- To determine the three-dimensional solution structure of the lambda-Cro repressor dimer.
- To compare the solution structure with its crystalline form and investigate potential conformational changes upon DNA binding.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy, including heteronuclear multidimensional techniques, was used for resonance assignment.
- Distance and dihedral angle constraints were derived from NMR data.
- Three-dimensional structures were calculated using simulated annealing.
Main Results:
- Nearly complete assignment of 1H, 15N, and 13C resonances for lambda-Cro repressor.
- Calculation of the 3D solution structure of the dimeric repressor using 1536 intra-subunit and 40 inter-subunit distance constraints.
- The solution structure of the monomer is similar to the crystalline form, but the dimer structure in solution differs, exhibiting potential distortion.
Conclusions:
- The study provides a detailed 3D structure of the lambda-Cro repressor in solution.
- Differences between solution and crystal dimer structures suggest conformational flexibility.
- The observed structural variations may be important for DNA recognition and binding specificity.