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Title: Neutron cryo-crystallography captures the protonation state of ferryl heme in a peroxidase
Authors: Casadei, Cecilia M.
Gumiero, Andrea
Metcalfe, Clive L.
Murphy, Emma J.
Basran, Jaswir
Concilio, Maria Grazia
Teixeira, Susana C. M.
Schrader, Tobias E.
Fielding, Alistair J.
Ostermann, Andreas
Blakeley, Matthew P.
Raven, Emma L.
Moody, Peter C. E.
First Published: 11-Jul-2014
Publisher: American Association for the Advancement of Science
Citation: Science, 2014, 345 (6193), pp. 193-197
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.
DOI Link: 10.1126/science.1254398
ISSN: 0036-8075
eISSN: 1095-9203
Version: Post-print
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2014, American Association for the Advancement of Science. Deposited with reference to the publisher’s open access archiving policy.
Description: This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science Magazine on 345(6193), DOI: 10.1126/science.1254398
Appears in Collections:Published Articles, Dept. of Chemistry

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