A set-up to study photochemically induced dynamic nuclear polarization in photosynthetic reaction centres by solid-state NMR.
Indian J Biochem Biophys
;
2000 Dec; 37(6): 418-23
Artigo
em Inglês
| IMSEAR
| ID: sea-27170
ABSTRACT
Recently, solid-state NMR spectroscopy became a viable method to investigate photosynthetic reaction centres (RCs) on the atomic level. To study the electronic structure of the radical cation state of the RC, occurring after the electron emission, solid-state NMR using an illumination set-up can be exploited. This paper describes the illumination set-up we designed for a standard Bruker wide-bore MAS NMR probe. In addition we demonstrate its application to get information from the active site in photosynthetic reaction centres of Rhodobacter sphaeroides R-26 by photochemically induced dynamic nuclear polarization (photo-CIDNP). Solid-state NMR spectra of natural abundance 13C in detergent solubilized quinone depleted photosynthetic reaction centres under continuous illumination showed exceptionally strong nuclear spin polarization in NMR lines. Both enhanced-absorptive and emissive polarization were seen in the carbon spectrum which could be assigned to a bacteriochlorophyll a (BChl a) cofactor, presumably the special pair BChl a. The sign and intensities of the 13C NMR signals provide information about the electron spin density distribution of the transiently formed radical P.+ on the atomic level.
Texto completo:
DisponíveL
Índice:
IMSEAR (Sudeste Asiático)
Assunto principal:
Fotoquímica
/
Rhodobacter sphaeroides
/
Ressonância Magnética Nuclear Biomolecular
/
Complexo de Proteínas do Centro de Reação Fotossintética
/
Complexos de Proteínas Captadores de Luz
Idioma:
Inglês
Revista:
Indian J Biochem Biophys
Ano de publicação:
2000
Tipo de documento:
Artigo
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