Neutron cryo-crystallography captures the protonation state of ferryl heme in a peroxidase

Casadei, CM, Gumiero, A, Metcalfe, CL, Murphy, EJ, Basran, J, Concilio, MG, Teixeira, SCM, Schrader, TE, Fielding, AJ, Ostermann, A, Blakeley, MP, Raven, EL and Moody, PCE (2014) Neutron cryo-crystallography captures the protonation state of ferryl heme in a peroxidase. Science, 345 (6193). pp. 193-197. ISSN 0036-8075

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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.

Item Type:	Article
Uncontrolled Keywords:	MD Multidisciplinary
Subjects:	Q Science > QD Chemistry Q Science > QH Natural history > QH301 Biology
Divisions:	Pharmacy and Biomolecular Sciences
Publisher:	American Association for the Advancement of Science
Date of acceptance:	29 May 2014
Date of first compliant Open Access:	26 February 2018
Date Deposited:	26 Feb 2018 11:18
Last Modified:	04 Sep 2021 10:44
DOI or ID number:	10.1126/science.1254398
URI:	https://ljmu-9.eprints-hosting.org/id/eprint/8122

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