Download MendeleyCryoradiolytic Reduction of Crystalline Heme Proteins: Analysis by Uv-Vis Spectroscopy and X-Ray Crystallography
Beitlich, T., Kuhnel, K., Schulze-Briese, C., Shoeman, R.L., Schlichting, I.(2007) J Synchrotron Radiat 14: 11
- PubMed: 17211068
- DOI: https://doi.org/10.1107/S0909049506049806
- Primary Citation of Related Structures:
2J18, 2J19 - PubMed Abstract:
The X-ray crystallographic analysis of redox-active systems may be complicated by photoreduction. Although radiolytic reduction by the probing X-ray beam may be exploited to generate otherwise short-lived reaction intermediates of metalloproteins, it is generally an undesired feature. Here, the X-ray-induced reduction of the three heme proteins myoglobin, cytochrome P450cam and chloroperoxidase has been followed by on-line UV-Vis absorption spectroscopy. All three systems showed a very rapid reduction of the heme iron. In chloroperoxidase the change of the ionization state from ferric to ferrous heme is associated with a movement of the heme-coordinating water molecule. The influence of the energy of the incident X-ray photons and of the presence of scavengers on the apparent reduction rate of ferric myoglobin crystals was analyzed.
Organizational Affiliation:
Max Planck Institute for Medical Research, Department of Biomolecular Mechanisms, Jahnstrasse 29, 69120 Heidelberg, Germany.
