Reaction center polypeptides

Trebst, A. (1987). The three dimensional structure of the herbicide binding niche on the reaction center polypeptide of photosystem II. 

Trebst, A., B. Depka, B. Kraft, and U. Johanningmeier (1988). The QB-site modulates the conformation of the photosystem II reaction center polypeptides. Photosynthesis Res., 18 163-177. 

C. Hydropathy Plots for the Bacterial Reaction-Center Polypeptides.51... 

Lam, Ortiz and Malkin further fractionated PSI-200 into the reaction-center core complex containing -100 chlorophyll molecules per P700, calling it PSI-KX), and the hght-harvesting chlorophyll-protein complex LHC I, as shown in Fig. 3 (B). Note that apart from the LHC I, PSI-100 retains the reaction-center polypeptide subunits, P700 and the three iron-sulfur proteins, Le.,... 

Mulo P, Laakso S, MaenpaS P et al. Stepwise photoinhibition of photosystem II. Studies with Synechocysds species PCC 6803 mutants with a modified D-E loop of the reaction center polypeptide Dl. Plant Physiol 1998 17 483-490. 

Trebst A. A contact site between the two reaction center polypeptides of photosystem II is involved in photoinhibition. Z Naturforsch 1991 46c 557-562. 

Substituted hydroxyquinolines are inhibitors of photosynthetic electron flow on the acceptor site of photosysten II. They displace radioactive netribuzin from its binding site on the D-1 reaction center polypeptide of photosysten II. They neither loose inhibitory potency in tris-treated membrane preparations, nor in a netribuzin resistant mutant of Cblamydomonas where serine 264 has been exchanged in the D-1 polypeptide. A QSAR study of 15 substituted bydroxyguino-lines suggests a dependency on two steric parameters and an electronic parameter for position 6. 

PURIFICATION AND C-TERMINAL SEQUENCE ANALYSIS OF PHOTOSYSTEM II REACTION CENTER POLYPEPTIDE, D1 AND D2. 

Photosystem II (PS II) of higher plant possess unique properties with respect to function, organization and protein turnover. It is a multisubunit protein complex which Is composed of at least 20 different polypeptides (1). The two reaction center polypeptides, designated D1 and D2, appear to carry all the redox components necessary for the primary photochemistry of PS II (2) and possibly also the Mn (3). The great majority of the PS II units is located in the appres-sed thylakold regions in association with its chlorophyll a/b antenna (4). PS II has a central catalytic role, but It also plays a central role In the long and short term acclimation of the photosynthetic apparatus. It Is also the target for the photoinhibition process which leads to Impaired electron transport capacity and the subsequent breakdown of the two reaction center subunits. In particular the Dl-protein. 

Clark, W.G., Davidson, E., and Marrs, B.L. (1984) Variation of levels of mRNA coding for antenna and reaction center polypeptides in Rhodopseudomonas capsulata in response to changes in oxygen concentration. J. Bacteriol. 157,945-948. 

Recently, the structures of the reaction centers from Rhodopseudomonas viridis and Rhodobacter sphaeroides have been solved at the atomic level (1,2). In both organisms the reaction center "core" polypeptides consist of the L and M subunits (responsible for charge separation), a cytochrome, and the H subunit (possibly required for stable assembly). It has become apparent that the bacterial reaction center, particularly the L and M subunits, can be directly compared to the reaction center polypeptides, D1 and D2, of Photosystem II (3). 

Purification and C-Terminal Sequence Analysis of Photosystem II Reaction Center Polypeptide, D1 and D2 311... 

Upon removal of LHCII, the remaining PSII consists of the core antenna polypeptides of PsbB (CP47) and PsbC (CP43) which bind only chlorophyll a and caroteniods. This core antenna is associated with the PSII reaction center polypeptides PsbA (Dl), PsbD (D2) which bind the redox carriers P680, Pheo, Qa and Qb. Thus, PSII is considered to be a Q-type or Type 2 reaction centre (Blankenship 2002) and was crystallized from the cyanobacterium, Synechococcus elongatus, to a 3.8 A resolution (Zouni et al., 2001). In contrast to PSII, removal of LHCI leaves the PSI reaction center polypeptides PsaA and PsaB which not only bind redox carriers but also bind the core antenna chlorophyll a and carotenoids associated with PSI. Thus, PSI is considered to be a Fe-S... 

A. Trebst (1987) The Three-Dimensional Structure of the Herbicide Binding Niche on the Reaction Center Polypeptide of Photosystem II. Z. Naturforsch. 42c, 272-750... 

Polyacrylamide gel electrophoresis (PAGE) was performed as described (15,16). PAGE of reaction centers gave the following results Mildly treated reaction centers (incubation at 50 C) resulted in the LM-reaction center polypeptides resolved as one complex with M of about 56 kD. Denaturation at lOO C for 10 minutes resulted in separation of the L and M subunits with M values of 27 kD and 29 kD, respectively. Some minor contaminations were often detected by the very sensitive silver staining method. The most dominant contamination has a M of about 10 kD. This protein is not a cytochrome as can be concluded from the absorption spectrum, it rather is a non-coloured component. 

Fig. 1. Coomassle stained polypeptides of whole thylakolds (Lane 1), granal (lane 2), and stromal (Lane 3) lamellae resolved by SDS-PAGE. The positions of photosystem 1 reaction center polypeptide (1), a and B subunits of proton ATFase (a, b), photosystem II reaction center polypeptides (rc 11),...

Nakatani HY Ke B Dolan E and Arntzen CJ (1984) Identity of the photosystem II reaction center polypeptide, submitted Rijgersberg CP Mel is A Amesz J and Swager JA (1979) Quenching of chlorophyll fluorescence and photochemical activity of chloroplasts at low temperature. In CIBA Foundation Symp 61, Chlorophyll Organization and Energy Transfer in Photosynthesis, pp 305-318. Amsterdam, Excerpta Medica Satoh K Nakatani HY Steinback KE Watson J and Arntzen CJ (1983) Polypeptide composition of a photosystem II core complex Presence of an herbicide binding protein. Biochim Biophys Acta, in press... 

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