Engineering of N‐terminal threonines in the D1 protein impairs photosystem II energy transfer in <i>Synechocystis</i> 6803

Funk, Christiane; Schröder, Wolfgang P.; Salih, Gaza F.; Wiklund, Ronney; Jansson, Christer

doi:10.1016/s0014-5793(98)01179-x

Cited by 11 publications

(14 citation statements)

References 36 publications

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“…The prominent peak at 685 nm in the 590 nm spectrum is linked to the phycobilisomes. This spectrum resembles that of the Synechocystis 6803 mutant T2V;T3V;T4V, where the energy transfer between the phycobilisomes and PSII is impaired [12,18]. A similar disruption in electron transfer is likely to explain the phenotype of the A0 mutant.…”

Section: Resultsmentioning

confidence: 70%

D1′ centers are less efficient than normal photosystem II centers

Funk¹,

Wiklund²,

Schröder³

et al. 2001

FEBS Letters

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One prominent difference between the photosystem II (PSII) reaction center protein D1P P in Synechocystis 6803 and normal D1 is the replacement of Phe-186 in D1 with leucine in D1P P. Mutants of Synechocystis 6803 producing only D1P P, or containing engineered D1 proteins with Phe-186 substitutions, were analyzed by 77 K fluorescence emission spectra, chlorophyll a fluorescence induction yield and decay kinetics, and flashinduced oxygen evolution. Compared to D1-containing PSII centers, D1P P centers exhibited a 50% reduction in variable chlorophyll a fluorescence yield, while the flash-induced O 2 evolution pattern was unaffected. In the F186 mutants, both the P680 + /Q Â recombination and O 2 oscillation pattern were noticeably perturbed. ß 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.

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Section: Resultsmentioning

confidence: 70%

D1′ centers are less efficient than normal photosystem II centers

Funk¹,

Wiklund²,

Schröder³

et al. 2001

FEBS Letters

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“…1). The 685-nm fluorescence emission band has been attributed to multiple sources, including charge recombination in PSII (49) and emission from the outer (light-harvesting complex) and inner (CP43 and CP47) antenna protein complexes (50). Mutagenesis studies suggest that the low-energy Chl ligated by His-114 of the CP47 protein gives rise to the 695-nm Chl fluorescence emission band (51).…”

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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“…We speculate, however, that the interaction between PBS and PSII, as influenced by Flv2/Flv4, is rather indirect and due to perturbation of the integrity of PSII dimers. Such perturbation also results from mutagenesis of specific subunits of PSII leading to a decrease in energy transfer efficiency from PBS to PSII (Funk et al, 1998;Veerman et al, 2005).…”

Section: Flv2/flv4 Heterodimer and Sll0218 Protein Are Functionally Lmentioning

confidence: 99%

Operon flv4-flv2 Provides Cyanobacterial Photosystem II with Flexibility of Electron Transfer

et al. 2012

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Synechocystis sp PCC 6803 has four genes encoding flavodiiron proteins (FDPs; Flv1 to Flv4). Here, we investigated the flv4-flv2 operon encoding the Flv4, Sll0218, and Flv2 proteins, which are strongly expressed under low inorganic carbon conditions (i.e., air level of CO 2 ) but become repressed at elevated CO 2 conditions. Different from FDP homodimers in anaerobic microbes, Synechocystis Flv2 and Flv4 form a heterodimer. It is located in cytoplasm but also has a high affinity to membrane in the presence of cations. Sll0218, on the contrary, resides in the thylakoid membrane in association with a high molecular mass protein complex. Sll0218 operates partially independently of Flv2/Flv4. It stabilizes the photosystem II (PSII) dimers, and according to biophysical measurements opens up a novel electron transfer pathway to the Flv2/Flv4 heterodimer from PSII. Constructed homology models suggest efficient electron transfer in heterodimeric Flv2/Flv4. It is suggested that Flv2/Flv4 binds to thylakoids in light, mediates electron transfer from PSII, and concomitantly regulates the association of phycobilisomes with PSII. The function of the flv4-flv2 operon provides many b-cyanobacteria with a so far unknown photoprotection mechanism that evolved in parallel with oxygen-evolving PSII.

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Engineering of N‐terminal threonines in the D1 protein impairs photosystem II energy transfer in Synechocystis 6803

Cited by 11 publications

References 36 publications

D1′ centers are less efficient than normal photosystem II centers

D1′ centers are less efficient than normal photosystem II centers

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

Operon flv4-flv2 Provides Cyanobacterial Photosystem II with Flexibility of Electron Transfer

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