Related Experiment Videos
ESR parameters for cupric bleomycin in the mobilized state
W E Antholine1, G Riedy, J S Hyde
1Department of Radiology, Medical College of Wisconsin, Milwaukee 53226.
Journal of Biomolecular Structure & Dynamics
|October 1, 1984
Summary
The copper complex of bleomycin (CuBlm) shows different ESR parameters in liquid versus solid states. Its structure appears to open and the copper ion shifts from the plane at room temperature.
Area of Science:
- Biochemistry
- Chemical Physics
- Molecular Biology
Background:
- The copper complex of bleomycin (CuBlm) is crucial for its biological activity.
- Previous X-ray studies suggested a pyramidal square planar configuration for CuBlm.
Purpose of the Study:
- To investigate the structural and electronic differences of CuBlm in liquid versus solid states using Electron Spin Resonance (ESR) spectroscopy.
- To elucidate the dynamic behavior and conformational changes of CuBlm in solution.
Main Methods:
- Electron Spin Resonance (ESR) spectroscopy, specifically S-band, was employed to study CuBlm.
- Computer simulations of ESR spectra were used to analyze hyperfine coupling constants and rotational correlation times.
Main Results:
- Significant differences in ESR parameters (Aiso, All, Al) were observed between liquid and solid states of CuBlm.
- Simulations indicated a change in the sign of Al and an increase in |All| in the liquid state.
- Rotational correlation time suggested non-spherical behavior and anisotropic motion of CuBlm in solution.
- Analysis of hyperfine coupling constants implies structural opening and displacement of the copper ion from the plane at room temperature.
Conclusions:
- CuBlm exhibits distinct structural and dynamic properties in liquid and solid states.
- The glycopeptide bleomycin complex undergoes conformational changes, opening its structure at room temperature.
- These findings provide insights into the molecular mechanisms underlying bleomycin's interaction with DNA.