BINUCLEAR MANGANESE(III) COMPLEXES AS ELECTRON-DONORS IN D1/D2/CYTOCHROME B559 PREPARATIONS ISOLATED FROM SPINACH PHOTOSYSTEM-II MEMBRANE-FRAGMENTS


ALLAKHVERDIEV S., KARACAN M. S. , SOMER G., KARACAN N., KHAN E., RANE S., ...More

ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES, vol.49, pp.587-592, 1994 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 49
  • Publication Date: 1994
  • Journal Name: ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.587-592
  • Keywords: PS II REACTION CENTER, MANGANESE, PHEOPHYTIN PHOTOACCUMULATION, NADP(+) REDUCTION, HIGHER-PLANTS, CHARGE SEPARATION, REACTION CENTERS, PHOTOREDUCTION, FLUORESCENCE, NADP+, CHLOROPHYLL, REQUIREMENT, PHEOPHYTIN, ACCEPTOR

Abstract

The capability of different manganese complexes to act as PS II electron donors in D1/D2/cytochrome b559 complexes has been analyzed by measuring actinic light-induced absorption changes at 680 nm (650 nm) and 340 nm, reflecting the photoaccumulation of Pheophytin(-) (Pheo(-)) and the reduction of NADP(+), respectively. The data obtained reveal: a) the donor capacity of synthetic binuclear Mn(III)(2) complexes containing aromatic ligands significantly exceeds that for MnCl2 in both cases, i.e. Pheo(-) photoaccumulation and NADP(+) reduction; b) manganese complexes can serve as suitable electron donors for light-induced NADP(+) reduction catalyzed by D1/D2/cytochrome b559 complexes and ferredoxin plus ferredoxin-NADP(+) reductase under anaerobic conditions and c) the specific turnover rate of the system leading to NADP(+) reduction is extremely small.