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Sub‐picosecond Raman spectrometer for time‐resolved studies of structural dynamics in heme proteins
Author(s) -
Kruglik Sergei G.,
Lambry JeanChristophe,
Martin JeanLouis,
Vos Marten H.,
Negrerie Michel
Publication year - 2011
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2685
Subject(s) - picosecond , raman spectroscopy , heme , chemistry , hemeprotein , raman scattering , coherent anti stokes raman spectroscopy , spectrometer , ultrafast laser spectroscopy , protein dynamics , femtosecond , diatomic molecule , photochemistry , analytical chemistry (journal) , laser , optics , molecular dynamics , molecule , physics , biochemistry , computational chemistry , organic chemistry , chromatography , enzyme
We describe a pump–probe Raman spectrometer based on a femtosecond Ti:sapphire laser, an optical parametric generator and two optical parametric amplifiers for time‐resolved studies, with emphasis on the structural dynamics in heme proteins. The system provides a 100‐fs pump pulse tunable in the range 500–600 nm and a transform‐limited sub‐picosecond probe pulse tunable in the range 390–450 nm. The spectrometer has spectral (25 cm −1 ) and temporal (∼0.7 ps) resolutions which constitute an effective compromise for identifying transient heme protein species and for following their structural evolution by spontaneous Raman scattering in the time range 0.5 ps to 2 ns. This apparatus was applied to time‐resolved studies of a broad range of heme proteins, monitoring the primary dynamics of photoinduced heme coordination state and structural changes, its interaction with protein side‐chains and diatomic gaseous ligands, as well as heme vibrational cooling. The treatment of transient Raman spectra is described in detail, and the advantages and shortcomings of spontaneous resonance Raman spectroscopy for ultrafast heme proteins studies are discussed. We demonstrate the efficiency of the constructed spectrometer by measuring Raman spectra in the sub‐picosecond and picosecond time ranges for the oxygen‐storage heme protein myoglobin and for the oxygen‐sensor heme protein FixLH in interaction with the diatomic gaseous ligands CO, NO, and O 2 . Copyright © 2010 John Wiley & Sons, Ltd.