Photooxidation of the Reaction Center Chlorophylls and Structural Properties of Photosynthetic Reaction Centers

Hoff, A.J.

doi:10.1007/978-3-642-81795-3_4

Cited by 15 publications

(9 citation statements)

References 197 publications

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“…Equation (3.14) can be written as W ab = 2-8.io*.n i *\J ab \x$e-* (3.15) with |J a6 | in Gauss and W ab in s" 1 . The maximal value of W ab for a given J ab is attained for x = \, so that (Hoff, 1982) W o6 (max) = 6 7 .io ( i |7 o 6 |s-1 .…”

Section: Esp Of Prereduced Reaction Centresmentioning

confidence: 99%

Electron spin polarization of photosynthetic reactants

Hoff

1984

Quart. Rev. Biophys.

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Photosynthesis is the conversion of the quantum energy of light into the chemical energy of complex organic molecules and organized cellular structures in plants and in some bacteria. The processes of photosynthesis span the time domain of subpicoseconds to the millennia of slow-growing trees, its study brings together such diverse disciplines as photophysics, biochemistry, botany and ecology. In the last few decades tremendous progress has been made in understanding the multivarious chemical reactions that ultimately lead to the fixation of carbon dioxide into organic substance, yet the basic mechanism underlying the conversion of photon energy into chemical energy still remains very much an enigma. These so-called primary reactions which transduce the excitation energy of excited chlorophyll pigments into the potential energy of stabilized, separated charges on electron donor and electron acceptor molecules have been studied with a variety of physical techniques, among which fast optical spectroscopy and electron paramagnetic resonance (EPR) are prominent. This review will highlight one intriguing aspect of EPR, namely that of electron spin polarization (ESP).† It will be shown that ESP of photosynthetic primary reactants offers a unique tool to gain insight in the electrostatic and magnetic interactions that make photosynthesis work. Moreover, it will become apparent that ESP in photosynthesis has several unique traits not (yet) found in ESP of photochemical reactions in vitro. As such, it may serve as a paradigma of ESP phenomena and will present an absorbing spectacle also for EPR spectroscopists outside photosynthesis.

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Section: Esp Of Prereduced Reaction Centresmentioning

confidence: 99%

Electron spin polarization of photosynthetic reactants

Hoff

1984

Quart. Rev. Biophys.

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“…Whether one or two chlorophyll a molecules participate in sharing the oxidized state of the primary donor, p+ -680, is a current and possibly partly semantic question (HoFF 1982). 9.1, this Vol.).…”

Section: Primary Electron Transfer Eventsmentioning

confidence: 99%

Energy Transduction in Oxygenic Photosynthesis: An Overview of Structure and Mechanism

Ort¹

1986

Photosynthesis III

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“…These processes take place in functional units called reaction centers (RCs) that have been isolated and are well characterized for a number of bacteria. Many different spectroscopic techniques have been used to identify and to characterize the electron transport sequence and the optical changes associated with it (Parson, 1982;Okamura et al, 1982;Hoff, 1982;Holten et al, 1978;Prince et al, 1977).…”

Section: Introductionmentioning

confidence: 99%

“…Charge separation and charge stabilization in the R C proceed at a remarkable efficiency, which is partly due to a highly organized arrangement of pigments, redox carriers and polypeptides (Hoff, 1982;Breton and Vermeglio, 1982;Tiede, in press;Breton and Nabedryk, 1984). The recent X-ray analysis of t h e crystallized R p s .…”

Section: Introductionmentioning

confidence: 99%

Light‐induced Fourier Transform Infrared Spectroscopic Investigations of the Intermediary Electron Acceptor Redution in Bacterial Photosynthesis

Nabedryk

Mäntele

Tavitian

et al. 1986

Photochem & Photobiology

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Abstract— Molecular changes associated with the light‐induced reduction of the intermediary electron acceptor I (bacteriopheophytin, BPh) in bacterial photosynthesis were studied by means of Fourier transform infrared (FTIR) difference spectroscopy. Chromatophore membranes and reconstituted reaction centers (RCs) of Rhodopseudomonas viridis were prereduced with sodium dithionite and illuminated in order to trap photochemically the state I−. Fourier transform infrared spectra of these samples were recorded before, during and after illumination, with an accuracy better than 10−3 absorbance units. Difference spectra of I− in chromatophores and in RCs closely correspond to each other. In the carbonyl stretching frequency region between 1640 and 1750 cm−1, bands are tentatively attributed to a shift (from 1713 to 1683 cm−1) of a keto carbonyl group, a change of an acetyl carbonyl grou at 1656 cm−1 and a decrease in absorbance strength of ester carbonyl groups (at 1746 and 1732 cm−P) after reduction of I. These groups likely belong to the BPh molecule, although at least one of the ester carbonyls could be assigned to an amino acid side chain. The absence of strong bands in the amide I and amide II region excludes large protein conformational changes associated with I reduction.

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Photooxidation of the Reaction Center Chlorophylls and Structural Properties of Photosynthetic Reaction Centers

Cited by 15 publications

References 197 publications

Electron spin polarization of photosynthetic reactants

Electron spin polarization of photosynthetic reactants

Energy Transduction in Oxygenic Photosynthesis: An Overview of Structure and Mechanism

Light‐induced Fourier Transform Infrared Spectroscopic Investigations of the Intermediary Electron Acceptor Redution in Bacterial Photosynthesis

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