Photo-induced oxidation of the uniquely liganded heme f in the cytochrome b6f complex of oxygenic photosynthesis.

ABSTRACT: The ultrafast behavior of the ferrous heme f from the cytochrome b6f complex of oxygenic photosynthesis is revealed by means of transient absorption spectroscopy. Benefiting from the use of microfluidic technologies for handling the sample as well as from a complementary frame-by-frame analysis of the heme dynamics, the different relaxation mechanisms from vibrationally excited states are disentangled and monitored via the shifts of the heme α-absorption band. Under 520 nm laser excitation, about 85% of the heme f undergoes pulse-limited photo-oxidation (<100 fs), with the electron acceptor being most probably one of the adjacent aromatic amino acid residues. After charge recombination in 5.3 ps, the residual excess energy is dissipated in 3.6 ps. In a parallel pathway, the remaining 15% o

SUBMITTER: Chauvet AA 

PROVIDER: S-EPMC4990003 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature