1 research outputs found
The Fate of the Triplet Excitations in the Fenna–Matthews–Olson Complex
The
fate of triplet excited states in the Fenna–Matthew–Olson
(FMO) pigment–protein complex is studied by means of time-resolved
nanosecond spectroscopy and exciton model simulations. Experiments
reveal microsecond triplet excited-state energy transfer between the
bacteriochlorophyll (BChl) pigments, but show no evidence of triplet
energy transfer to molecular oxygen, which is known to produce highly
reactive singlet oxygen and is the leading cause of photo damage in
photosynthetic proteins. The FMO complex is exceptionally photo stable
despite the fact it contains no carotenoids, which could effectively
quench triplet excited states of (bacterio)Âchlorophylls and are usually
found within pigment–protein complexes. It is inferred that
the triplet excitation is transferred to the lowest energy pigment,
BChl 3, within the FMO complex, whose triplet state energy is shifted
by pigment–protein interactions below that of the singlet oxygen
excitation. Thus, the energy transfer to molecular oxygen is blocked
and the FMO does not need carotenoids for photo protection