Premium
Protochlorophyllide a: A Comprehensive Photophysical Picture
Author(s) -
Dietzek Benjamin,
Tschierlei Stefanie,
Hermann Gudrun,
Yartsev Arkady,
Pascher Torbjörn,
Sundström Villy,
Schmitt Michael,
Popp Jürgen
Publication year - 2009
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200800536
Subject(s) - protochlorophyllide , photochemistry , chemistry , excited state , fluorescence , nanosecond , substrate (aquarium) , triplet state , spectroscopy , protoporphyrin ix , fluorescence spectroscopy , oxidoreductase , excitation , optics , enzyme , laser , molecule , atomic physics , physics , organic chemistry , quantum mechanics , oceanography , geology
The photochemistry of protochlorophyllide a, a precursor in the biosynthesis of chlorophyll and substrate of the light regulated enzyme protochlorophyllide oxidoreductase, is investigated by pump‐probe spectroscopy. Upon excitation into the lowest lying Q‐band the light induced changes are recorded over a wide range of probe wavelengths in the visible and near‐IR region between 500 and 1000 nm. Following excitation, an initial ultrafast 450 fs process is observed related to the motion out of the Franck‐Condon region on the excited state surface; thus directly unraveling previous suggestions based on time‐resolved fluorescence measurements ( ChemPhysChem 2006 , 7 , 1727–1733). Furthermore, the data reveals a previously concealed photointermediate, whose formation on a nanosecond timescale matches the overall fluorescence decay and is assigned to a triplet state. The implications of this finding with respect to the photochemistry of NADPH:protochlorophyllide oxidoreductase (POR) are discussed.