Determination of the Molar Extinction Coefficients of the B800 and B850 Absorption Bands in Light-harvesting Complexes 2 Derived from Three Purple Photosynthetic Bacteria Rhodoblastus acidophilus, Rhodobacter sphaeroides, and Phaeospirillum molischianum by Extraction of Bacteriochlorophyll a

Photoreaction centres are Nature's solar batteries. These nanometre-scale power producers are responsible for transducing the energy of sunlight into a form that can be used by biological systems, thereby powering most of the biological activity on the planet. Although to the layman the word ‘photosynthesis’ is usually associated with green plants, much of our understanding of the molecular basis of biological transduction of light energy has come from studies of purple photosynthetic bacteria. Their RCs (reaction centres) and attendant light-harvesting complexes have been subjected to an intensive spectroscopic scrutiny, coupled with genetic manipulation and structural studies, that has revealed many of the molecular and mechanistic details of biological energy transfer, electron transfer and coupled proton translocation. This review provides a short overview of the structure and mechanism of the purple bacterial RC, focusing in the main on the most heavily studied complex from Rhodobacter sphaeroides.

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ChemInform Abstract: Determination of Integrated Molar Extinction Coefficients for IR Absorption Bands of Pyridine Adsorbed on Solid Acid Catalysts.

ChemInform ◽

10.1002/chin.199338056 ◽

2010 ◽

Vol 24 (38) ◽

pp. no-no ◽

Cited By ~ 2

Author(s):

C. A. EMEIS

Keyword(s):

Solid Acid ◽

Solid Acid Catalysts ◽

Ir Absorption ◽

Acid Catalysts ◽

Absorption Bands ◽

Extinction Coefficients ◽

Molar Extinction Coefficients

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Bacteriochlorophyll interaction with singlet oxygen in membranes of purple photosynthetic bacteria: does the protective function of carotenoids exist?

Доклады Академии наук ◽

10.31857/s0869-56524864504-508 ◽

2019 ◽

Vol 486 (4) ◽

pp. 504-508

Author(s):

Z. K. Makhneva ◽

A. A. Ashikhmin ◽

M. A. Bolshakov ◽

A. A. Moskalenko

Keyword(s):

Singlet Oxygen ◽

Photosynthetic Bacteria ◽

Light Harvesting ◽

Direct Action ◽

Light Harvesting Complexes ◽

Protective Function ◽

Classic Work ◽

Purple Photosynthetic Bacteria ◽

Apoptosis Process ◽

Mutant Cells

The direct action of singlet oxygen on the bacteriochlorophyll (BChl) of light-harvesting complexes in the membranes of four types of purple non-sulfur and sulfur photosynthesizing bacteria with and without carotenoids has been studied. It has been found that BChl in carotenoid-less samples is generally more resistant to the action of singlet oxygen compared to the control. It is assumed that carotenoids are not needed to protect BChl of bacterial light-harvesting complexes from singlet oxygen, and in the classic work of Griffith et al. [1] the apoptosis process in carotenoid-less mutant cells, which involves the destruction of complexes, the appearance of monomeric BChl and generation of singlet oxygencaused by BChl, followed by BChl oxidation, was mistakenly attributed to the protective function of carotenoids.

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