Long-range electron transfer in rigid 3(10)-helical oligopeptides containing redox cyclic alpha-amino acids.
Photochem Photobiol
; 70(4): 579-84, 1999 Oct.
Article
en En
| MEDLINE
| ID: mdl-10546555
ABSTRACT
Intrahelical photoinduced electron transfer processes (ET) in conformationally restricted oligopeptides have been studied by nanosecond time-resolved transient spectroscopy. The helical peptides were constructed from sterically hindered alpha-aminoisobutyric acid (Aib) and two cyclic alpha-amino acids (Aib class) bearing electron acceptor and donor side chains (DkNap, ThQx). This helical backbone design provides high conformation stability, as previously demonstrated, and yields reliable 3(10)-helical architectures in solution. The forward ET between ThQx and 3DkNap is followed by a slow back ET thus giving rise to an accumulation of the charge-separated ion pairs for hundreds of nanoseconds. We demonstrate the modulation of electronic interactions by the number of intervening Aib residues separating acceptor-donor side chains and propose modifications of the peptide framework by inclusion of a non-Aib amino acid residue. These well-defined and sterically stable frameworks are suited for the precise evaluation of intrahelical electron transfer processes mediated by peptides.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oligopéptidos
Idioma:
En
Revista:
Photochem Photobiol
Año:
1999
Tipo del documento:
Article
País de afiliación:
Estados Unidos