Related Experiment Video
Updated: May 12, 2026

Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling
Published on: March 20, 2018
Oxygen activation and redox partner binding in cytochromes P450
Thomas L Poulos1, Yarrow Madrona
1Departments of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, USA.
Abstract:
The structural underpinnings of O₂ activation in P450s have been limited by the inability to trap unstable oxy complexes in the crystalline state for structure determination. To date there are only two known oxy P450 structures. Even so, much is known about O₂ activation in P450cam and the role that redox partner binding plays in this process. Of particular importance are changes in the I helix associated with O₂ binding that enable "catalytic" waters to enter the active site and establish an H-bonding network essential for cleavage of the O--O bond. The changes in the I helix are similar to differences in the substrate-bound (closed) and substrate-free (open) conformations. With this information in hand, we have solved the structure of the substrate-free form of P450cin as well as the nitric oxide complex as a mimic of the oxy complex. This information provides some insight into the similarities and differences between P450cin and P450cam in O₂ activation.
More Related Videos
12:08Monitoring the Reductive and Oxidative Half-Reactions of a Flavin-Dependent Monooxygenase using Stopped-Flow Spectrophotometry
Published on: March 18, 2012
08:31Anaerobic Protein Purification and Kinetic Analysis via Oxygen Electrode for Studying DesB Dioxygenase Activity and Inhibition
Published on: October 3, 2018
Related Concept Videos
Oxidation of Phenols to Quinones
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Redox Reactions
Redox Reactions
Bioactivation and Tissue Toxicity
Electron Transport Chain: Complex III and IV
Oxidation and Reduction of Organic Molecules
The removal of an electron from a molecule, results in a...