Tryptophan at Position 181 of the D2 Protein of Photosystem II Confers Quenching of Variable Fluorescence of Chlorophyll:  Implications for the Mechanism of Energy-Dependent Quenching†

Biochemistry ◽  
1999 ◽  
Vol 38 (44) ◽  
pp. 14690-14696 ◽  
Author(s):  
Dmitrii V. Vavilin ◽  
Svetlana Y. Ermakova-Gerdes ◽  
Anna T. Keilty ◽  
Wim F. J. Vermaas
Keyword(s):  
Photosystem Ii ◽  
Variable Fluorescence ◽  
Energy Dependent ◽  
D2 Protein

scholarly journals Targeted Random Mutagenesis To Identify Functionally Important Residues in the D2 Protein of Photosystem II in Synechocystis sp. Strain PCC 6803

2001 ◽  
Vol 183 (1) ◽  
pp. 145-154 ◽  
Author(s):  
Svetlana Ermakova-Gerdes ◽  
Zhenbao Yu ◽  
Wim Vermaas
Keyword(s):  
Photosystem Ii ◽  
Screening Method ◽  
Random Mutagenesis ◽  
Terminal Part ◽  
Photoautotrophic Growth ◽  
Intragenic Complementation ◽  
Novel Method ◽  
Α Helix ◽  
D2 Protein ◽  
Pcc 6803

ABSTRACT To identify important residues in the D2 protein of photosystem II (PSII) in the cyanobacterium Synechocystis sp. strain PCC 6803, we randomly mutagenized a region of psbDI (coding for a 96-residue-long C-terminal part of D2) with sodium bisulfite. Mutagenized plasmids were introduced into a Synechocystissp. strain PCC 6803 mutant that lacks both psbD genes, and mutants with impaired PSII function were selected. Nine D2 residues were identified that are important for PSII stability and/or function, as their mutation led to impairment of photoautotrophic growth. Five of these residues are likely to be involved in the formation of the QA-binding niche; these are Ala249, Ser254, Gly258, Ala260, and His268. Three others (Gly278, Ser283, and Gly288) are in transmembrane α-helix E, and their alteration leads to destabilization of PSII but not to major functional alterations of the remaining centers, indicating that they are unlikely to interact directly with cofactors. In the C-terminal lumenal tail of D2, only one residue (Arg294) was identified as functionally important for PSII. However, from the number of mutants generated it is likely that most or all of the 70 residues that are susceptible to bisulfite mutagenesis have been altered at least once. The fact that mutations in most of these residues have not been picked up by our screening method suggests that these mutations led to a normal photoautotrophic phenotype. A novel method of intragenic complementation in Synechocystissp. strain PCC 6803 was developed to facilitate genetic analysis ofpsbDI mutants containing several amino acid changes in the targeted domain. Recombination between genome copies in the same cell appears to be much more prevalent in Synechocystis sp. strain PCC 6803 than was generally assumed.

Site-Directed Mutations of Two Histidine Residues in the D2 Protein Inactivate and Destabilize Photosystem II in the Cyanobacterium Synechocystis 6803

1987 ◽  
Vol 42 (7-8) ◽  
pp. 762-768 ◽  
Author(s):  
Wim F. J. Vermaas ◽  
John G. K. Williams ◽  
Charles J. Arntzen
Keyword(s):  
Low Temperature ◽  
Photosystem Ii ◽  
Purple Bacteria ◽  
Synechocystis 6803 ◽  
Ps Ii ◽  
Histidine Residues ◽  
Fluorescence Maximum ◽  
Herbicide Binding ◽  
Chlorophyll Protein ◽  
D2 Protein

Site-directed mutations were created in the cyanobacterium Synechocystis 6803 to alter specific histidine residues of the photosystem II (PS II) D2 protein. In one mutant (tyr-197). the his-197 residue was replaced by tyrosine, in another mutant (asn-214), his-214 was changed into asparagine. The tyr-197 mutant did not show any low-temperature fluorescence attributable to PS II. but contained a PS II chlorophyll-protein, CP-47, in significant quantities. Another PS II chlorophyll-protein, CP-43, was absent, as was PS II-related herbicide binding. The asn-214 mutant showed a blue-shifted low-temperature fluorescence maximum around 682 nm. but did not have a significant amount of membrane-incorporated CP-43 or CP-47. Herbicide binding was also absent in this mutant. These data indicate a very important role of the his-197 and his-214 residues in the D 2 protein, and are interpreted to support the hypothesis that the D2 protein and the M subunit from the photosynthetic reaction center of purple bacteria have analogous functions. According to this hypothesis, his-197 is involved in binding of P680. and his-214 forms ligands with Qᴀ and Fe2+. In absence of a functional D2 protein, the PS II core complex appears to be destabilized as evidenced by loss of chlorophyll-proteins in the mutants.

Increased Synthesis of Photosystem II in Triticum vulgare when Grown in the Presence of BAS 13-338

1984 ◽  
Vol 39 (5) ◽  
pp. 510-514 ◽  
Author(s):  
Salil Bose ◽  
R. Mannar Mannan ◽  
C.J. Arntzen
Keyword(s):  
Photosystem Ii ◽  
Primary Electron ◽  
Fluorescence Induction ◽  
Sublethal Dose ◽  
Chlorophyll Fluorescence Induction ◽  
Hill Reaction ◽  
Variable Fluorescence ◽  
Triticum Vulgare ◽  
Primary Electron Acceptor ◽  
Saturated Intensity

Addition of BAS 13-338 (4-chloro-5-dimethylamino-2-phenyl-3(2H)-pyridazinone) to a suspension of chloroplast thylakoids caused an increase in the / level of chlorophyll fluorescence induction without affecting the F0 level and with a slight decrease in the Fmax level in a manner similar to the addition of DCMU to a thylakoid suspension. Addition of BAS 13-338 also inhibited the rate of Hill reaction H2O → dichlorophenol indophenol with 50% inhibition occurring at about 10 μм BAS 13-338. The inhibition was not reversed by diphenyl carbazide used as an artificial electron donor to photosystem II. These results suggest that the site of inhibition by BAS 13-338 is between Q (next to the primary electron acceptor) and plastoquinone.When the plants were grown in the presence of sublethal dose of BAS 13-338, the following changes were noted in the thylakoids of the treated plants as compared to the thylakoids isolated from the control plants: The F0 and the normalized variable fluorescence (⊿F/F0) levels increased, chlorophyll a/b ratio decreased, chlorophyll/P700 ratio increased. Furthermore, the rate of photosystem II electron transport both under saturated intensity and the limiting intensity of illumination increased, and the ratio of plastoquinone to Q decreased. These observations have been interpreted as due to an increase in the ratio of photosystem II to photosystem I in plants grown in the presence of BAS 13-338.

scholarly journals Accumulation of the D2 Protein Is a Key Regulatory Step for Assembly of the Photosystem II Reaction Center Complex inSynechocystisPCC 6803

2004 ◽  
Vol 279 (47) ◽  
pp. 48620-48629 ◽  
Author(s):  
Josef Komenda ◽  
Veronika Reisinger ◽  
Bernd Christian Müller ◽  
Marika Dobáková ◽  
Bernhard Granvogl ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Reaction Center ◽  
Reaction Center Complex ◽  
D2 Protein

A possible relation between the function of photosystem II in oxygen evolution and the variable chlorophyll fluorescence

1989 ◽  
Vol 238 (1291) ◽  
pp. 127-136
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Reaction Centre ◽  
Redox Potentials ◽  
Donor Side ◽  
Hypothetical Model ◽  
Surplus Energy ◽  
Variable Chlorophyll Fluorescence ◽  
And Function ◽  
Energy Dependent

A hypothetical model for the structure and function of photosystem II is proposed that attempts to incorporate different phenomena related to the variable chlorophyll fluorescence inherent in this photosystem. The involvement of pheophytin redox chemistry on both the acceptor and donor side of photosystem II is postulated to achieve redox potentials high enough to oxidize water. The presence of this symmetry would be the cause of inefficient photochemistry in photosystem II when, under unbalanced carbon metabolism, a surplus charge remains on the reaction centre. In addition, such a scheme would enable an efficient dissipation of surplus energy in the reaction centre itself, and would be the origin ofthe ‘energy-dependent’ quenching of chlorophyll fluorescence, q ( E ).

scholarly journals A reversibly induced CRISPRi system targeting Photosystem II in the cyanobacterium Synechocystis sp. PCC 6803

2020 ◽  
Author(s):  
Deng Liu ◽  
Virginia M. Johnson ◽  
Himadri B. Pakrasi
Keyword(s):  
Photosystem Ii ◽  
Sole Carbon Source ◽  
Model Organism ◽  
Inducible Promoter ◽  
New Strategy ◽  
Photosynthetic Complexes ◽  
Promoter System ◽  
Synechocystis Sp ◽  
D2 Protein ◽  
Pcc 6803

ABSTRACTThe cyanobacterium Synechocystis sp. PCC 6803 is used as a model organism to study photosynthesis, as it can utilize glucose as the sole carbon source to support its growth under heterotrophic conditions. CRISPR interference (CRISPRi) has been widely applied to repress the transcription of genes in a targeted manner in cyanobacteria. However, a robust and reversible induced CRISPRi system has not been explored in Synechocystis 6803 to knock down and recover the expression of a targeted gene. In this study, we built a tightly controlled chimeric promoter, PrhaBAD-RSW, in which a theophylline responsive riboswitch was integrated into a rhamnose-inducible promoter system. We applied this promoter to drive the expression of ddCpf1 (DNase-dead Cpf1 nuclease) in a CRISPRi system and chose the PSII reaction center gene psbD (D2 protein) to target for repression. psbD was specifically knocked down by over 95% of its native expression, leading to severely inhibited Photosystem II activity and growth of Synechocystis 6803 under photoautotrophic conditions. Significantly, removal of the inducers rhamnose and theophylline reversed repression by CRISPRi. Expression of PsbD recovered following release of repression, coupled with increased Photosystem II content and activity. This reversibly induced CRISPRi system in Synechocystis 6803 represents a new strategy for study of the biogenesis of photosynthetic complexes in cyanobacteria.

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