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Sub‐Picosecond Mid‐Infrared Spectroscopy of Phytochrome Agp1 from Agrobacterium tumefaciens
Author(s) -
Schumann Christian,
Groß Ruth,
Michael Norbert,
Lamparter Tilman,
Diller Rolf
Publication year - 2007
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.200700210
Subject(s) - picosecond , chromophore , excited state , spectroscopy , photochemistry , chemistry , isomerization , quantum yield , phytochrome , flash photolysis , ground state , reaction rate constant , atomic physics , physics , optics , kinetics , laser , organic chemistry , biology , fluorescence , quantum mechanics , catalysis , red light , botany
Abstract The photoinduced primary reaction of the biliverdin binding phytochrome Agp1 (Agp1‐BV) from Agrobacterium tumefaciens was investigated by sub‐picosecond time‐resolved Vis pump–IR probe spectroscopy. Three time constants of τ 1 =0.7±0.05 ps, τ 2 =3.3±0.2 ps and τ 3 =33.3±1.5 ps could be isolated from the dynamics of structurally specific marker bands of the BV chromophore. These results together with those of accompanying sub‐picosecond Vis pump–Vis probe spectroscopy allow the extension of the reaction scheme for the primary process by a vibrationally excited electronic ground state. The isomerization at the C15C16 bond occurs within the lifetime of the excited electronic state. A quantum yield of 0.094 for the primary reaction is determined, suggesting that the quantum yield of formation of the P fr far‐red‐absorbing form is already established in the primary photoreaction of the P r (red‐absorbing) form.