Short-lived metal-centered excited state initiates iron-methionine photodissociation in ferrous cytochrome c
Open Access
- 17 February 2021
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nature Communications
- Vol. 12 (1), 1-8
- https://doi.org/10.1038/s41467-021-21423-w
Abstract
The dynamics of photodissociation and recombination in heme proteins represent an archetypical photochemical reaction widely used to understand the interplay between chemical dynamics and reaction environment. We report a study of the photodissociation mechanism for the Fe(II)-S bond between the heme iron and methionine sulfur of ferrous cytochrome c. This bond dissociation is an essential step in the conversion of cytochrome c from an electron transfer protein to a peroxidase enzyme. We use ultrafast X-ray solution scattering to follow the dynamics of Fe(II)-S bond dissociation and 1s3p (Kβ) X-ray emission spectroscopy to follow the dynamics of the iron charge and spin multiplicity during bond dissociation. From these measurements, we conclude that the formation of a triplet metal-centered excited state with anti-bonding Fe(II)-S interactions triggers the bond dissociation and precedes the formation of the metastable Fe high-spin quintet state.Keywords
Funding Information
- U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (P41GM103393)
This publication has 51 references indexed in Scilit:
- Energy transfer and relaxation mechanisms in Cytochrome cChemical Physics, 2012
- Femtosecond UV Studies of the Electronic Relaxation Processes in Cytochrome cThe Journal of Physical Chemistry B, 2011
- Tracking the structural dynamics of proteins in solution using time-resolved wide-angle X-ray scatteringNature Methods, 2008
- Ultrafast dynamics of ligands within heme proteinsBiochimica et Biophysica Acta (BBA) - Bioenergetics, 2008
- Fe L-Edge X-ray Absorption Spectroscopy of Low-Spin Heme Relative to Non-heme Fe Complexes: Delocalization of Fe d-Electrons into the Porphyrin LigandJournal of the American Chemical Society, 2006
- Investigations of Heme Protein Absorption Line Shapes, Vibrational Relaxation, and Resonance Raman Scattering on Ultrafast Time ScalesThe Journal of Physical Chemistry A, 2003
- Electronic structure and bonding in unligated and ligated FeII porphyrinsThe Journal of Chemical Physics, 2002
- VMD: Visual molecular dynamicsJournal of Molecular Graphics, 1996
- High-resolution three-dimensional structure of horse heart cytochrome cJournal of Molecular Biology, 1990
- Photophysics and reactivity of heme proteins: a femtosecond absorption study of hemoglobin, myoglobin, and protohemeBiochemistry, 1988