article · 29/06/2006
Ultrafast heme dynamics in ferrous versus ferric cytochrome c studied by time-resolved resonance Raman and transient absorption spectroscopy
Résumé
Cytochrome c (Cyt c) is a heme protein involved in electron transfer and also in apoptosis. Its heme iron is bisaxially ligated to histidine and methionine side chains and both ferric and ferrous redox states are physiologically relevant, as well as a ligand exchange between internal residue and external diatomic molecule. The photodissociation of internal axial ligand was observed for several ferrous heme proteins including Cyt c, but no time-resolved studies have been reported on ferric Cyt c. To investigate how the oxidation state of the heme influences the primary photoprocesses, we performed a comprehensive comparative study on horse heart Cyt c by subpicosecond time-resolved resonance Raman and femtosecond transient absorption spectroscopy. We found that in ferric Cyt c, in contrast to ferrous Cyt c, the photodissociation of an internal ligand does not take place, and relaxation dynamics is dominated by vibrational cooling in the ground electronic state of the heme. The intermolecular vibrational energy transfer was found to proceed in a single phase with a temperature decay of similar to 7 ps in both ferric and ferrous Cyt c. For ferrous Cyt c, the instantaneous photodissociation of the methionine side chain from the heme iron is the dominant event, and its rebinding proceeds in two phases, with time constants of similar to 5 and similar to 16 ps. A mechanism of this process is discussed, and the difference in photoinduced coordination behavior between ferric and ferrous Cyt c is explained by an involvement of the excited electronic state coupled with conformational relaxation of the heme.
Citer cet article
Negrerie, M., Cianetti, S., Vos, M., Martin, J., & Kruglik, S.-G. (2006). Ultrafast heme dynamics in ferrous versus ferric cytochrome c studied by time-resolved resonance Raman and transient absorption spectroscopy. Journal of Physical Chemistry B, 110(25), 12766-12781. https://doi.org/10.1021/jp0559377@article{Negrerie2006_69,
author = {Negrerie, M and Cianetti, S and Vos, MH and Martin, JL and Kruglik, Sergei G},
year = {2006},
month = {6},
title = {Ultrafast heme dynamics in ferrous versus ferric cytochrome c studied by time-resolved resonance Raman and transient absorption spectroscopy},
journal = {Journal of Physical Chemistry B},
publisher = {AMER CHEMICAL SOC},
volume = {110},
number = {25},
pages = {12766-12781},
address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
abstract = {Cytochrome c (Cyt c) is a heme protein involved in electron transfer and also in apoptosis. Its heme iron is bisaxially ligated to histidine and methionine side chains and both ferric and ferrous redox states are physiologically relevant, as well as a ligand exchange between internal residue and external diatomic molecule. The photodissociation of internal axial ligand was observed for several ferrous heme proteins including Cyt c, but no time-resolved studies have been reported on ferric Cyt c. To investigate how the oxidation state of the heme influences the primary photoprocesses, we performed a comprehensive comparative study on horse heart Cyt c by subpicosecond time-resolved resonance Raman and femtosecond transient absorption spectroscopy. We found that in ferric Cyt c, in contrast to ferrous Cyt c, the photodissociation of an internal ligand does not take place, and relaxation dynamics is dominated by vibrational cooling in the ground electronic state of the heme. The intermolecular vibrational energy transfer was found to proceed in a single phase with a temperature decay of similar to 7 ps in both ferric and ferrous Cyt c. For ferrous Cyt c, the instantaneous photodissociation of the methionine side chain from the heme iron is the dominant event, and its rebinding proceeds in two phases, with time constants of similar to 5 and similar to 16 ps. A mechanism of this process is discussed, and the difference in photoinduced coordination behavior between ferric and ferrous Cyt c is explained by an involvement of the excited electronic state coupled with conformational relaxation of the heme.},
url = {http://www.dx.doi.org/10.1021/jp0559377},
doi = {10.1021/jp0559377},
issn = {1520-6106},
}TY - JOUR
AU - Negrerie, M
AU - Cianetti, S
AU - Vos, MH
AU - Martin, JL
AU - Kruglik, Sergei G
PY - 2006
DA - 2006/06/29
TI - Ultrafast heme dynamics in ferrous versus ferric cytochrome c studied by time-resolved resonance Raman and transient absorption spectroscopy
JO - Journal of Physical Chemistry B
VL - 110
IS - 25
PB - AMER CHEMICAL SOC
SN - 1520-6106
AB - Cytochrome c (Cyt c) is a heme protein involved in electron transfer and also in apoptosis. Its heme iron is bisaxially ligated to histidine and methionine side chains and both ferric and ferrous redox states are physiologically relevant, as well as a ligand exchange between internal residue and external diatomic molecule. The photodissociation of internal axial ligand was observed for several ferrous heme proteins including Cyt c, but no time-resolved studies have been reported on ferric Cyt c. To investigate how the oxidation state of the heme influences the primary photoprocesses, we performed a comprehensive comparative study on horse heart Cyt c by subpicosecond time-resolved resonance Raman and femtosecond transient absorption spectroscopy. We found that in ferric Cyt c, in contrast to ferrous Cyt c, the photodissociation of an internal ligand does not take place, and relaxation dynamics is dominated by vibrational cooling in the ground electronic state of the heme. The intermolecular vibrational energy transfer was found to proceed in a single phase with a temperature decay of similar to 7 ps in both ferric and ferrous Cyt c. For ferrous Cyt c, the instantaneous photodissociation of the methionine side chain from the heme iron is the dominant event, and its rebinding proceeds in two phases, with time constants of similar to 5 and similar to 16 ps. A mechanism of this process is discussed, and the difference in photoinduced coordination behavior between ferric and ferrous Cyt c is explained by an involvement of the excited electronic state coupled with conformational relaxation of the heme.
SP - 12766
EP - 12781
DO - 10.1021/jp0559377
UR - http://www.dx.doi.org/10.1021/jp0559377
ER -