The primary reaction of photosystem II in the D1‐D2‐cytochrome <i>b</i>‐559 complex

Danielius, R.; Satoh, Kimiyuki; Kan, Paul J. M. van; Plijter, Johan J.; Nuijs, Antonius M.; Gorkom, Hans J. van

doi:10.1016/0014-5793(87)81498-9

Cited by 147 publications

(63 citation statements)

References 11 publications

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“…Therefore, we will restrict our analysis to the fast component, which we attribute to charge separation based on past work (37,45). Finally, the nondecaying component is believed to reflect the fully chargeseparated state of the RC (P680 ϩ -Pheo Ϫ ), which has a lifetime of 36 ns at ambient temperature (45,62,63).…”

Section: Resultsmentioning

confidence: 99%

Functional asymmetry of photosystem II D1 and D2 peripheral chlorophyll mutants of Chlamydomonas reinhardtii

Wang

Gosztola

Ruffle

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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The peripheral accessory chlorophylls (Chls) of the photosystem II (PSII) reaction center (RC) are coordinated by a pair of symmetryrelated histidine residues (D1-H118 and D2-H117). These Chls participate in energy transfer from the proximal antennae complexes (CP43 and CP47) to the RC core chromophores. In addition, one or both of the peripheral Chls are redox-active and participate in a low-quantum-yield electron transfer cycle around PSII. We demonstrate that conservative mutations of the D2-H117 residue result in decreased Chl fluorescence quenching efficiency attributed to reduced accumulation of the peripheral accessory Chl cation, Chl Z ؉ . In contrast, identical symmetry-related mutations at residue D1-H118 had no effect on A mong the photosynthetic organisms, there are two different, quinone-type photosynthetic reaction centers (RCs): the oxygenic type present in chloroplasts and cyanobacteria (photosystem II, PSII) and the nonoxygenic type (bacterial reaction center, BRC) as typified by that in purple-sulfur photosynthetic bacteria (for reviews, see refs. 1 and 2). In 1984, the crystal structure of the Rhodopseudomonas viridis BRC was determined at 3-Å resolution by Deisenhofer et al. (3). It soon was recognized that the L and M polypeptides of the BRC had substantial amino acid sequence similarity with the PSII D1 and D2 proteins, respectively. Early models of the D1 and D2 proteinfolding topologies indicated that the PSII D1 and D2 polypeptides were structurally analogous to the L and M subunits (3-8). These models of the PSII RC polypeptides and their associated cofactors were verified by electron and x-ray diffraction of twoand three-dimensional PSII crystals (9-12). Recently, a 3.8-Å resolution structure of the oxygen-evolving PSII complex from Synechecoccus elongatus was determined (13).The PSII RC has six chlorophylls (Chls), two pheophytins (Pheos), two quinones, and one cytochrome b 559 (Cyt b 559 ) heme (8, 13). Significantly, the PSII RC has two additional Chls, relative to the BRC. Site-directed mutagenesis and spectroscopic studies demonstrated that the additional pair of Chls present in PSII is coordinated by a pair of conserved and C 2 symmetryrelated histidine residues (D1-H118 and D2-H117, Chlamydomonas reinhardtii nomenclature) (14-20). Unlike the four Chls and two Pheos involved in primary charge separation, the additional pair of Chls present in the PSII RC is located on the periphery of D1 and D2 polypeptides.Biophysical evidence for the involvement of the peripheral Chls in energy transfer first was obtained from analysis of P680 oxidation kinetics by Schelvis et al. (14). They observed a Ϸ30-ps P680 oxidation lifetime component, which they attributed to energy transfer from a Chl monomer to P680. Based on a Förster mechanism (21) for energy transfer, they calculated that the distance between the peripheral Chl and P680 was 30 Å, a distance confirmed by the recent PSII crystal structure. A similar distance relationship also was predicted on the basis of Chl fluorescence decay kine...

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Section: Resultsmentioning

confidence: 99%

Functional asymmetry of photosystem II D1 and D2 peripheral chlorophyll mutants of Chlamydomonas reinhardtii

Wang

Gosztola

Ruffle

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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“…More recently, Nanba and Satoh (24) reported the isolation of a PSII complex composed of Dl, D2, and Cyt b-559 which they identified as the RC. Danielius et al (9) confirmed this identification by showing that the material could transfer an electron from P680 to endogenous pheophytin. In this paper we confirm the isolation of the Nanba-Satoh preparation and report on several spectral properties that appear to relate to the stability of the isolated PSII reaction center.…”

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confidence: 85%

Spectral, Photophysical, and Stability Properties of Isolated Photosystem II Reaction Center

Seibert¹,

Picorel²,

Rubin³

et al. 1988

Plant Physiol.

146

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Photosystem II reaction center (RC) preparations isolated from spinach (Spinacea oleracea) by the Nanba-Satoh procedure (O Nanba, K Satoh 1987 Proc Nati Acad Sci USA 84: 109-112) are quite labile, even at 4°C in the dark. Simple spectroscopic criteria were developed to characterize the native state of the material. Degradation of the RC results in (a) blueshifting of the red-most absorption maximum, (b) a shift of the 77 K fluorescence maximum from -682 nm to -670 nm, and (c) a shift of fluorescence lifetime components from 1.3-4 nanoseconds and >25 nanoseconds to -6-7 nanoseconds. Fluorescence properties at 77 K seem to be a more sensitive spectral indicator of the integrity of the material. The >25 nanosecond lifetime component is assigned to P680+ Pheophytinrecombination luminescence, which suggests a correlation between the observed spectral shifts and the photochemical competence of the preparation. Substitution of lauryl maltoside for Triton X-100 immediately after RC isolation stabilizes the RCs and suggests that Triton may be responsible for the instability.RC4 complexes found in photosynthetic membranes contain specialized pigment components that carry out the primary photochemical processes of photosynthesis. These light reactions provide the chemical potential to drive dark electron transport that leads to the storage of energy required by the organism. The first RC fractions were isolated from the photosynthetic bacteria Rhodobacter sphaeroides R-26 (25) and Rhodospirillum rubrum S1 (14) in the late 1960s. This accomplishment has led to a great deal of progress in understanding of the function of the RC. Perhaps the most far-reaching effect of this work, however, culminated in the crystallization of the Rhodopseudomonas viridis RC, which was the first integral membrane protein complex to be crystallized (22 (8,10,18) have suggested that the Dl and D2 proteins constitute the reaction center of PSII. The first experimental evidence suggesting that this might be true was the observation that the Dl protein functions or affects function on both sides of the PSII RC (21). More recently, Nanba and Satoh (24) reported the isolation of a PSII complex composed of Dl, D2, and Cyt b-559 which they identified as the RC. Danielius et al. (9) confirmed this identification by showing that the material could transfer an electron from P680 to endogenous pheophytin. In this paper we confirm the isolation of the Nanba-Satoh preparation and report on several spectral properties that appear to relate to the stability of the isolated PSII reaction center.MATERIALS AND METHODS PSII RC fractions were prepared from market spinach (Spinacia oleracea) by the procedure of Nanba and Satoh (24). All steps were carried out at 4°C in the dark. Appressed thylakoid membrane fragments devoid of PSI (13) were obtained from market spinach using Triton X-100 (17). PSII membranes were pelleted and then resuspended in 50 mm Tris-HCl (pH 7.2). The material (30 ml of 1 mg Chl/ml final concentration) was then stirred for 1 h with 4%...

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“…charge separated state of the RC (P680+-Pheo a-), which has been shown by nanosecond experiments to have a lifetime of 36 ns at ambient temperature [40]. The difficulties in reliably fitting a triple exponential decay with the modest signal-to-noise (typically about 50 at this pump energy) inherent in transient absorption experiments is well known.…”

Section: Kinetics At 544 Nm With 200 Nj Pump Pulsesmentioning

confidence: 99%

Wavelength and intensity dependent primary photochemistry of isolated Photosystem II reaction centers at 5°C

Greenfield¹,

Seibert²,

Wasielewski³

1996

Chemical Physics

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The long wavelength absorption band of the isolated Photosystem II reaction center was directly excited at five wavelengths between 655 and 689 nm to study the effects of excitation wavelength and intensity on both excitation energy transfer and charge separation processes. Subpicosecond transient absorption measurements were made monitoring principally the bleach of the pheophytin a Qx band at 544 nm. At all pump wavelengths, the kinetics require three exponentials (1-3, 10-25 and 50-100 ps) to be fit properly. The pump energy was varied by a factor of twenty-five (40-1000 nJ), with no apparent effect on either the rates or the amplitude ratios of the three components, although clear evidence of nonlinear behavior was observed at the higher excitation energies. The dependence of both the rates and amplitude ratios of the three components upon pump wavelength will be discussed in terms of excitation energy transfer occurring on a 30 ps timescale. Selective excitation into the short and long-wavelength sides of the composite Qy band give identical transient spectra at 500 ps, indicating near-unity efficiency of excitation energy transfer. At 1 ps, the spectra are quite different, calling into question the extent of ultrafast ( ~ 100 fs) excitation energy transfer. The time after the excitation pulse at which the transient crosses A A = 0 was found to be a highly sensitive measure of both the excitation energy and the identity of the pigment pool that had been excited.

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The primary reaction of photosystem II in the D1‐D2‐cytochrome b‐559 complex

Cited by 147 publications

References 11 publications

Functional asymmetry of photosystem II D1 and D2 peripheral chlorophyll mutants of Chlamydomonas reinhardtii

Functional asymmetry of photosystem II D1 and D2 peripheral chlorophyll mutants of Chlamydomonas reinhardtii

Spectral, Photophysical, and Stability Properties of Isolated Photosystem II Reaction Center

Wavelength and intensity dependent primary photochemistry of isolated Photosystem II reaction centers at 5°C

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