green fluorescent protein;
resonance Raman;
density functional theory;
vibrational spectroscopy;
D O I:
10.1016/S0022-2860(00)00825-5
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
Infrared absorption (IR), Raman, and resonance Raman spectra have been obtained from 500 to 1700 cm(-1) for 4-hydroxybenzylidene-2,3-dimethyl-imidazolinone (HBDI), an analog of the green-fluorescent protein (GFP) chromophore. Numerous transitions are evident in both the IR and Raman spectra, with the resonance Raman spectrum of HBDI dominated by a subset of transitions in the 1430-1700 cm(-1) region. Assignment of the transitions in this frequency region to the corresponding normal coordinates is accomplished through computational studies employing density functional and Hartree-Fock theory. The computational results indicate that the vibrational transitions in this frequency range are dominated by in-plane stretching modes that are localized to the imidazolinone or tyrosine portions of the chromophore, rather than being delocalized over the entire chromophore. No evidence is obtained for significant excited-state structural evolution along the O-H stretching coordinate. The implications of these findings with respect to the excited-state proton transfer dynamics of GFP are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.