# Ultrafast Dynamics in Flavocytochrome C by Using Transient Absorption and Femtosecond Fluorescence Lifetime Spectroscopy

## TL;DR

This paper studies the ultrafast behavior of a key enzyme in sulfur metabolism using advanced spectroscopy techniques.

## Contribution

The study reveals new insights into the ultrafast dynamics of flavocytochrome c using transient absorption and femtosecond fluorescence.

## Key findings

- Photoexcited species in FccAB decay nonradiatively within the first few picoseconds.
- Transient absorption identifies two dynamic processes: internal conversion (~400 fs) and vibrational cooling (~4 ps).
- These processes primarily affect the heme part of the flavocytochrome.

## Abstract

Flavocytochrome c sulfide dehydrogenase (FCC) is an important
enzyme
of sulfur metabolism in sulfur-oxidizing bacteria, and its catalytic
properties have been extensively studied. However, the ultrafast dynamics
of FCC is not well understood. We present ultrafast transient absorption
and fluorescence spectroscopy measurements to unravel the early events
upon excitation of the heme and flavin chromophores embedded in the
flavocytochrome c (FccAB) from the bacterium Thiocapsa
roseopersicina. The fluorescence kinetics of FccAB
suggests that the majority of the photoexcited species decay nonradiatively
within the first few picoseconds. Transient absorption spectroscopy
supports these findings by suggesting two major dynamic processes
in FccAB, internal conversion occurring in about 400 fs and the vibrational
cooling occurring in about 4 ps, mostly affecting the heme moiety.