Ultrafast fluorescence dynamics of tryptophan in the proteins monellin and IIAGlc.
J Am Chem Soc
; 128(4): 1214-21, 2006 Feb 01.
Article
em En
| MEDLINE
| ID: mdl-16433538
ABSTRACT
The complete time-resolved fluorescence of tryptophan in the proteins monellin and IIA(Glc) has been investigated, using both an upconversion spectrophotofluorometer with 150 fs time resolution and a time-correlated single photon counting apparatus on the 100 ps to 20 ns time scale. In monellin, the fluorescence decay displays multiexponential character with decay times of 1.2 and 16 ps, and 0.6, 2.2, and 4.2 ns. In contrast, IIA(Glc) exhibited no component between 1.2 ps and 0.1 ns. For monellin, surprisingly, the 16 ps fluorescence component was found to have positive amplitude even at longer wavelengths (e.g., 400 nm). In conjunction with quantum mechanical simulation of tryptophan in monellin, the experimental decay associated spectra (DAS) and time-resolved emission spectra (TRES) indicate that this fluorescence decay time should be ascribed to a highly quenched conformer. Recent models (Peon, J.; et al. Proc. Natl.Acad. Sci. U.S.A. 2002, 99, 10964) invoked exchange-coupled relaxation of protein water to explain the fluorescence decay of monellin.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
/
Triptofano
/
Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato
/
Proteínas de Escherichia coli
Idioma:
En
Revista:
J Am Chem Soc
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Estados Unidos