Evaluation of selected benzoquinones, naphthoquinones, and anthraquinones as replacements for phylloquinone in the A sub 1 acceptor site of the photosystem I reaction center

Journal Article · Tue Aug 07 00:00:00 EDT 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00483a014· OSTI ID:6086533

Biggins, J ^[1]

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1. Brown Univ., Providence, RI (USA)

Selected substituted 1,4-benzoquinones, 1,4-naphthoquinones, and 9,10-anthraquinones were investigated as possible replacement quinones in spinach photosystem I (PSI) preparations that had been depleted of endogenous phylloquinone by extraction with hexane/methanol. As a criterion for successful biochemical reconstitution, the restoration of electron transfer was determined by measuring P-430 turnover at room temperature from flash-induced absorbance transients. Restoration of complete electron transfer between A{sub 0}{sup {minus}} and P-430 (terminal iron-sulfur centers, F{sub A}F{sub B}) was demonstrated by using phylloquinone, 2-methyl-3-decyl-1,4-naphthoquinone, 2-methyl-3-(isoprenyl){sub 2}-1,4-naphthoquinone, and 2-methyl-3-(isoprenyl){sub 4}-1,4-naphthoquinone. All other quinones tested did not restore P-430 turnover but acted as electron acceptors and oxidized A{sub 0}{sup {minus}}. It is concluded that the specificity of the replacement quinone for interaction with the primary acceptor, A{sub 0}{sup {minus}}, is low but additional structural constraints are required for the quinone occupying the A{sub 1} site to donate to the iron-sulfur center, F{sub x}. It is suggested that the 3-phytyl side chain of phylloquinone and the 3-alkyl tails of the three naphthoquinones that restored P-430 turnover may be required for interaction with a hydrophobic domain of the A{sub 1} site in the PSI core to promote electron transfer to F{sub x} and then to F{sub A}F{sub B}.

• OSTI ID: 6086533
• Journal Information: Biochemistry; (USA), Vol. 29:31; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
PHOTOSYNTHETIC REACTION CENTERS
ELECTRON TRANSFER
QUINONES
REDOX POTENTIAL
ABSORPTION SPECTROSCOPY
BENZOQUINONES
PHOTOSYNTHESIS
PHOTOSYNTHETIC MEMBRANES
SPINACH
AROMATICS
CHEMICAL REACTIONS
FOOD
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MEMBRANES
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
SPECTROSCOPY
SYNTHESIS
VEGETABLES
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)