Optically Detected Magnetic Resonance (ODMR) of Triplet States in Photosynthesis

Hoff, A.J.

doi:10.1007/0-306-47960-5_17

Cited by 8 publications

(11 citation statements)

References 55 publications

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“…viridis crystal structure appeared in 1984 it confirmed the by then well established idea that P is a dimer of BChl molecules (see [34,59,84,87,124] for recent experiments), and was also readily consistent with the idea that one BPh is an electron carrier between P and QA. The nomenclature of BPhL and BChl L on a photoactive branch leading to QA, and BPhM and BChlM on a non-photoactive branch, was adopted.…”

Section: Reaction Center Primary Photochemistrysupporting

confidence: 71%

Primary photochemistry of reaction centers from the photosynthetic purple bacteria

1987

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Photosynthetic organisms transform the energy of sunlight into chemical potential in a specialized membrane-bound pigment-protein complex called the reaction center. Following light activation, the reaction center produces a charge-separated state consisting of an oxidized electron donor molecule and a reduced electron acceptor molecule. This primary photochemical process, which occurs via a series of rapid electron transfer steps, is complete within a nanosecond of photon absorption. Recent structural data on reaction centers of photosynthetic bacteria, combined with results from a large variety of photochemical measurements have expanded our understanding of how efficient charge separation occurs in the reaction center, and have changed many of the outstanding questions.

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Section: Reaction Center Primary Photochemistrysupporting

confidence: 71%

Primary photochemistry of reaction centers from the photosynthetic purple bacteria

1987

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“…Triplet-triplet transfer proceeds via the Dexter mechanism (Dexter 1953), which requires the overlap of electronic orbitals, hence a close proximity between donor and acceptor molecules. The absorbance detected magnetic resonance technique (ADMR) has been employed in isolated antenna complexes (see Hoff 1986 for a review) to detect the Triplet-minusSinglet spectra showing interaction bands between the carotenoid and the nearby chlorophyll molecules which are excitonically coupled to it. In this way information regarding the chlorophyll forms on which the triplet state is originally populated has been derived.…”

Section: Resultsmentioning

confidence: 99%

A Fluorescence Detected Magnetic Resonance Investigation of the Carotenoid Triplet States Associated with Photosystem II of Isolated Spinach Thylakoid Membranes

et al. 2005

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The carotenoid triplet populations associated with the fluorescence emission chlorophyll forms of Photosystem II have been investigated in isolated spinach thylakoid membranes by means of fluorescence detected magnetic resonance in zero field (FDMR). The spectra collected in the 680-690 nm emission range, have been fitted by a global analysis procedure. At least five different carotenoid triplet states coupled to the terminal emitting chlorophyll forms of PS II, peaking at 682 nm, 687 nm and 692 nm, have been characterised. The triplets associated with the outer antenna emission forms, at 682 nm, have zero field splitting parameters |D| = 0.0385 cm-1, |E| = 0.00367 cm-1; |D| = 0.0404 cm-1, |E| = 0.00379 cm-1 and |D| = 0.0386 cm-1, |E| = 0.00406 cm-1 which are very similar to those previously reported for the xanthophylls of the isolated LHC II complex. Therefore the FDMR spectra recorded in this work provide insights into the organisation of the LHC II complex in the unperturbed environment represented by thylakoid membranes. The additional carotenoid triplet populations, detected by monitoring the chlorophyll emission at 687 and 692 nm, are assigned to carotenoids bound to inner antenna complexes and hence attributed to beta-carotene molecules.

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“…The interactions between the primary donors and the other cofactors present in the reaction centers, have been largely investigated by ODMR, in different organisms (Aust et al 1990;Angerhofer et al 1994;Bordignon et al 2002;Carbonera et al 1994Carbonera et al , 1997Carbonera et al , 2002Giacometti et al 2007;Hoff 1982Hoff , 1989Hoff , 1996Santabarbara et al 2003Santabarbara et al , 2007Ullrich et al 1987;Witt et al 2002Witt et al , 2003Krabben et al 2000). Recently, site-directed mutants of photosynthetic bacteria and green algae have been studied by ODMR, giving new insights about the effect of the protein environment on the electronic properties of the cofactors in close vicinity of the primary donor (Vrieze et al 1996a, b;Witt et al 2002Witt et al , 2003Krabben et al 2000).…”

Section: Odmr In Photosynthesismentioning

confidence: 98%

“…A fruitful field of application has proven to be Photosynthesis. An important contribution to this field has been given by Hoff, especially in improving the ADMR technique (for a review, see Hoff 1996).…”

Section: Odmr Of Triplet Statesmentioning

confidence: 99%

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Optically detected magnetic resonance (ODMR) of photoexcited triplet states

Carbonera

2009

Photosynth Res

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Optically Detected Magnetic Resonance (ODMR) is a double resonance technique which combines optical measurements (fluorescence, phosphorescence, absorption) with electron spin resonance spectroscopy. After the first triplet-state ODMR experiments in zero magnetic field reported in 1968 by Schmidt and van der Waals, the number of double resonance studies on excited triplet states grew rapidly. Photosynthesis has proven to be a fruitful field of application due to the intrinsic possibility of forming photo-induced pigment triplet states in many sites of the photosynthetic apparatus. The basic principles of this technique are described and examples of application in Photosynthesis are reported.

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Optically Detected Magnetic Resonance (ODMR) of Triplet States in Photosynthesis

Cited by 8 publications

References 55 publications

Primary photochemistry of reaction centers from the photosynthetic purple bacteria

Primary photochemistry of reaction centers from the photosynthetic purple bacteria

A Fluorescence Detected Magnetic Resonance Investigation of the Carotenoid Triplet States Associated with Photosystem II of Isolated Spinach Thylakoid Membranes

Optically detected magnetic resonance (ODMR) of photoexcited triplet states

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