Download MendeleyNeutron Cryo-Crystallography Captures the Protonation State of Ferryl Heme in a Peroxidase
Casadei, C.M., Gumiero, A., Metcalfe, C.L., Murphy, E.J., Basran, J., Concilio, M.G., Teixeira, S.C.M., Schrader, T.E., Fielding, A.J., Ostermann, A., Blakeley, M.P., Raven, E.L., Moody, P.C.E.(2014) Science 345: 193
- PubMed: 25013070
- DOI: https://doi.org/10.1126/science.1254398
- Primary Citation of Related Structures:
4CVI, 4CVJ - PubMed Abstract:
Heme enzymes activate oxygen through formation of transient iron-oxo (ferryl) intermediates of the heme iron. A long-standing question has been the nature of the iron-oxygen bond and, in particular, the protonation state. We present neutron structures of the ferric derivative of cytochrome c peroxidase and its ferryl intermediate; these allow direct visualization of protonation states. We demonstrate that the ferryl heme is an Fe(IV)=O species and is not protonated. Comparison of the structures shows that the distal histidine becomes protonated on formation of the ferryl intermediate, which has implications for the understanding of O-O bond cleavage in heme enzymes. The structures highlight the advantages of neutron cryo-crystallography in probing reaction mechanisms and visualizing protonation states in enzyme intermediates.
Organizational Affiliation:
Department of Biochemistry and Henry Wellcome Laboratories for Structural Biology, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK. Institut Laue-Langevin, 71 Avenue des Martyrs, 38000, Grenoble, France.
