Open AccessMammalian complex III heme dynamics studied with pump-probe spectroscopy and red light illuminations
Author(s) -
Sean P. O’Connor,
Samantha M. Powell,
John M. Rickman,
Nathaniel J. Pope,
Gary D. Noojin,
Marlan O. Scully,
Michael L. Denton,
Vladislav V. Yakovlev
Publication year - 2021
Publication title -
biomedical optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.441118
Subject(s) - heme , photodissociation , spectroscopy , ultrafast laser spectroscopy , absorption spectroscopy , chemistry , photochemistry , electron transfer , optics , physics , biochemistry , quantum mechanics , enzyme
The electronic or molecular mechanisms that initiate photobiomodulation (PBM) in cells are not yet fully understood. The porcine complex III (C-III) of the electron transport chain was characterized with transient absorption spectroscopy (TAS). We then applied our recently developed continuous wave laser coupled TAS procedure (CW-TAS) to investigate the effect of red light irradiances on the heme dynamics of C-III in its c 1 reduced state. The time constants were found to be 3.3 ± 0.3 ps for vibrational cooling of the oxidized state and 4.9 ± 0.4 ps for rebinding of the photodissociated axial ligand of the c 1 reduced state. The analysis of the CW-TAS procedure yielded no significant changes in the C-III heme dynamics. We rule out the possibility of 635 nm CW light at 4.7 mW/cm 2 inducing a PBM effect on the heme dynamic of C-III, specifically with the photodissociation of its axial ligand.