scholarly journals Subunit composition of CP43-less photosystem II complexes of Synechocystis sp. PCC 6803: implications for the assembly and repair of photosystem II

2012 ◽  
Vol 367 (1608) ◽  
pp. 3444-3454 ◽  
Author(s):  
M. Boehm ◽  
J. Yu ◽  
V. Reisinger ◽  
M. Beckova ◽  
L. A. Eichacker ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Gel Electrophoresis ◽  
Photochemical Activity ◽  
Subunit Composition ◽  
Null Mutant ◽  
Trap Potential ◽  
Native Gel ◽  
Oxygen Evolving ◽  
Pcc 6803

Photosystem II (PSII) mutants are useful experimental tools to trap potential intermediates involved in the assembly of the oxygen-evolving PSII complex. Here, we focus on the subunit composition of the RC47 assembly complex that accumulates in a psbC null mutant of the cyanobacterium Synechocystis sp. PCC 6803 unable to make the CP43 apopolypeptide. By using native gel electrophoresis, we showed that RC47 is heterogeneous and mainly found as a monomer of 220 kDa. RC47 complexes co-purify with small Cab-like proteins (ScpC and/or ScpD) and with Psb28 and its homologue Psb28-2. Analysis of isolated His-tagged RC47 indicated the presence of D1, D2, the CP47 apopolypeptide, plus nine of the 13 low-molecular-mass (LMM) subunits found in the PSII holoenzyme, including PsbL, PsbM and PsbT, which lie at the interface between the two momomers in the dimeric holoenzyme. Not detected were the LMM subunits (PsbK, PsbZ, Psb30 and PsbJ) located in the vicinity of CP43 in the holoenzyme. The photochemical activity of isolated RC47-His complexes, including the rate of reduction of P680 + , was similar to that of PSII complexes lacking the Mn 4 CaO 5 cluster. The implications of our results for the assembly and repair of PSII in vivo are discussed.

scholarly journals Protection of the Oxygen-Evolving Machinery by the Extrinsic Proteins of Photosystem II is Essential for Development of Cellular Thermotolerance in Synechocystis sp. PCC 6803

2002 ◽  
Vol 43 (8) ◽  
pp. 932-938 ◽  
Author(s):  
Aiko Kimura ◽  
Julian J. Eaton-Rye ◽  
Eugene H. Morita ◽  
Yoshitaka Nishiyama ◽  
Hidenori Hayashi
Keyword(s):  
Photosystem Ii ◽  
Extrinsic Proteins ◽  
Oxygen Evolving ◽  
Synechocystis Sp ◽  
Pcc 6803

scholarly journals Involvement of the HtrA family of proteases in the protection of the cyanobacterium Synechocystis PCC 6803 from light stress and in the repair of photosystem II

2002 ◽  
Vol 357 (1426) ◽  
pp. 1461-1468 ◽  
Author(s):  
Paulo Silva ◽  
Young–Jun Choi ◽  
Hanadi A. G. Hassan ◽  
Peter J. Nixon
Keyword(s):  
Photosystem Ii ◽  
Light Stress ◽  
High Light ◽  
Triple Mutant ◽  
D1 Polypeptide ◽  
In The Wild ◽  
D1 Turnover ◽  
Major Target ◽  
Pcc 6803

Photosystem II (PSII) is prone to irreversible light–induced damage, with the D1 polypeptide a major target. Repair processes operate in the cell to replace a damaged D1 subunit within the complex with a newly synthesized copy. As yet, the molecular details of PSII repair are relatively obscure despite the critical importance of this process for maintaining PSII activity and cell viability. We are using the cyanobacterium Synechocystis sp. PCC 6803 to identify the various proteases and chaperones involved in D1 turnover in vivo . Two families of proteases are being studied: the FtsH family (four members) of Zn 2+ –activated nucleotide–dependent proteases; and the HtrA (or DegP) family (three members) of serine–type proteases. In this paper, we report the results of our studies on a triple mutant in which all three copies of the htrA gene family have been inactivated. Growth of the mutant on agar plates was inhibited at high light intensities, especially in the presence of glucose. Oxygen evolution measurements indicated that, under conditions of high light, the rate of synthesis of functional PSII was less in the mutant than in the wild–type. Immunoblotting experiments conducted on cells blocked in protein synthesis further indicated that degradation of D1 was slowed in the mutant. Overall, our observations indicate that the HtrA family of proteases are involved in the resistance of Synechocystis 6803 to light stress and play a part, either directly or indirectly, in the repair of PSII in vivo .

scholarly journals Change in subunit composition of the iron protein of nitrogenase from Rhodospirillum rubrum during activation and inactivation of iron protein

1982 ◽  
Vol 205 (3) ◽  
pp. 489-494 ◽  
Author(s):  
G G Preston ◽  
P W Ludden
Keyword(s):  
Nitrogen Source ◽  
Gel Electrophoresis ◽  
Rhodospirillum Rubrum ◽  
Subunit Composition ◽  
Iron Protein ◽  
Fe Protein ◽  
Lower Band

The subunit composition of the Fe protein of nitrogenase from Rhodospirillum rubrum during activation and inactivation was investigated. It was found that the upper subunit (on gel electrophoresis) of the two-subunit Fe protein was converted into the lower subunit during activation in vitro. When the Fe protein was inactivated in vivo by the addition of NH4Cl and alpha-oxoglutarate to the cells, a phosphate-labelled upper band appeared. During activation in vitro by the activating enzyme, some of the phosphate of the upper band remained with the protein and appeared in the lower band. Activations in vitro were performed on inactive Fe protein obtained from cells grown with glutamate as the nitrogen source. Both native and oxygen-denatured Fe protein exhibited the loss of upper band during treatment with activating enzyme.

Quantitative assessment of the high-light tolerance in plants with an impaired photosystem II donor side

2019 ◽  
Vol 476 (9) ◽  
pp. 1377-1386 ◽  
Author(s):  
Sam Wilson ◽  
Alexander V. Ruban
Keyword(s):  
Photosystem Ii ◽  
Redox State ◽  
Photochemical Quenching ◽  
Oxygen Evolving Complex ◽  
Reaction Centre ◽  
Donor Side ◽  
Acceptor Side ◽  
Oxygen Evolving ◽  
The Impact

Abstract Photoinhibition is the light-induced down-regulation of photosynthetic efficiency, the primary target of which is photosystem II (PSII). Currently, there is no clear consensus on the exact mechanism of this process. However, it is clear that inhibition can occur through limitations on both the acceptor- and donor side of PSII. The former mechanism is caused by electron transport limitations at the PSII acceptor side. Whilst, the latter mechanism relies on the disruption of the oxygen-evolving complex. Both of these mechanisms damage the PSII reaction centre (RC). Using a novel chlorophyll fluorescence methodology, RC photoinactivation can be sensitively measured and quantified alongside photoprotection in vivo. This is achieved through estimation of the redox state of QA, using the parameter of photochemical quenching in the dark (qPd). This study shows that through the use of PSII donor-side inhibitors, such as UV-B and Cd2+, there is a steeper gradient of photoinactivation in the systems with a weakened donor side, independent of the level of NPQ attained. This is coupled with a concomitant decline in the light tolerance of PSII. The native light tolerance is partially restored upon the use of 1,5-diphenylcarbazide (DPC), a PSII electron donor, allowing for the balance between the inhibitory pathways to be sensitively quantified. Thus, this study confirms that the impact of donor-side inhibition can be detected alongside acceptor-side photoinhibition using the qPd parameter and confirms qPd as a valid, sensitive and unambiguous parameter to sensitively quantify the onset of photoinhibition through both acceptor- or donor-side mechanisms.

Alterations of the Oxygen-Evolving Apparatus Induced by a305Arg →305Ser Mutation in the CP43 Protein of Photosystem II fromSynechocystissp. PCC 6803 under Chloride-Limiting Conditions†

Biochemistry ◽  
2002 ◽  
Vol 41 (52) ◽  
pp. 15747-15753 ◽  
Author(s):  
Andrew Young ◽  
Myriam McChargue ◽  
Laurie K. Frankel ◽  
Terry M. Bricker ◽  
Cindy Putnam-Evans
Keyword(s):  
Photosystem Ii ◽  
Oxygen Evolving ◽  
Pcc 6803
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