Photosystem II oxidation of charged electron donors. Surface charge effects

Yerkes, Christine T.; Babcock, Gerald T.

doi:10.1016/0005-2728(80)90207-8

Cited by 64 publications

(45 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These data indicate that Asc provided electrons to PSII via Tyr Z + . Earlier EPR data obtained with artificial electron donors are in agreement with the involvement of Tyr Z in the reaction pathway between Asc and PSII (Yerkes and Babcock, 1980). We investigated the occurrence of alternative electron donors in different photosynthetic organisms, including the cyanobacterium Synechocystis PCC 6803, the green alga Chlamydomonas reinhardtii, the moss Marchantia polymorpha, the fern Nephrolepis exaltata, the coniferous plant Juniperus chinensis, as well as in pea and Agropyron elongatum ('Szarvasi-1'; a new variety of tall wheatgrass that is produced in Hungary for its biomass).…”

Section: Asc-dependent Electron Transfer In Thylakoids Isolated From supporting

confidence: 70%

Experimental Evidence for Ascorbate-Dependent Electron Transport in Leaves with Inactive Oxygen-Evolving Complexes

et al. 2009

View full text Add to dashboard Cite

Previously, we showed that in barley (Hordeum vulgare) leaves with heat-inactivated oxygen-evolving complexes, photosystem II (PSII) has access to a large pool of alternative electron donors. Based on in vitro data, we proposed that this donor was ascorbate, yet this hypothesis has not been substantiated in vivo. In this paper, with the aid of chlorophyll a fluorescence induced by short (5-ms) light pulses and 820-nm absorbance transient measurements on wild-type and ascorbate-deficient (vtc2-1) mutant leaves of Arabidopsis (Arabidopsis thaliana), we show that in heat-treated leaves the rate of electron donation to PSII as well as the 3-(3,4-dichlorophenyl)-1,1-dimethylurea-sensitive electron transport toward photosystem I depend on the ascorbate content of the leaves: upon ascorbate treatment, the donation half-time in the wild type and the mutant decreased from 25 to 22 ms and from 55 to 32 ms, respectively. Thermoluminescence measurements show that Tyr Z + is involved in the electron transfer from ascorbate to PSII. These data and the similar ascorbate dependencies of the heat-treated and the tris(hydroxymethyl)aminomethane-treated thylakoid membranes, with maximal donation half-times of about 16 ms, show that ascorbate is capable of supporting a sustained electron transport activity in leaves containing inactivated oxygen-evolving complexes. This alternative electron transport appears to be ubiquitous in the plant kingdom and is present in the green alga Chlamydomonas reinhardtii, and its rate depends on the physiological state of the plants and on environmental conditions. Our data suggest that ascorbate, as an alternative PSII electron donor, plays a physiological role in heat-stressed plants.

show abstract

Section: Asc-dependent Electron Transfer In Thylakoids Isolated From supporting

confidence: 70%

Experimental Evidence for Ascorbate-Dependent Electron Transport in Leaves with Inactive Oxygen-Evolving Complexes

et al. 2009

View full text Add to dashboard Cite

show abstract

“…This means that photosynthesis was limited either by the reduction of the reaction-centre chlorophyll P680 § after primary charge separation orand by the function of the antenna system. Addition of diphenylcarbazide, which is an artificial electron donor that passes electrons immediately to Z (Yerkes and Babcock 1980), did not enhance the low PSII activity of thylakoids of red-light-treated Acetabularia cells (Wennicke and Schmid 1987). This indicates that the rereduction does not limit PSII activity in red light at least before or at the site of diphenylcarbazide action.…”

Section: Discussionmentioning

confidence: 69%

Quantitative correlation of peripheral and intrinsic core polypeptides of photosystem II with photosynthetic electron-transport activity ofAcetabularia mediterranea in red and blue light

Schmid

Wennicke

Fleischhauer

1990

Planta

View full text Add to dashboard Cite

The high photosynthetic activity (O2 production and CO2 consumption) ofAcetabularia mediterranea Lamour. (=A. acetabulum (L.) Silva) characteristic of cells cultured in white light decreases slowly when cells are kept in continuous red light, and is less than 20% of the original activity after three weeks. Subsequent blue irradiation restores the original activity completely within 3-5 d. The polypeptide composition of the thylakoids from cells grown in either red or blue light and after transfer from red to blue light was analyzed mainly with regards to photosystem II (PSII). The P700-containing reaction-centre complex of photosystem I, CPI, showed only minor quantitative alterations as a consequence of the growth-light quality, which correlated well with the activity of photosystem I under these conditions. In PSII, no drastic changes occurred in the quantity of the reaction-centre components D1 (herbicide-binding polypeptide) and D2, as determined by immunoblots. Likewise, the proteins associated with the water-splitting apparatus did not change detectably in thylakoids from red- or blue-light-treated cells (the 16-kDa component could not be found inAcetabularia thylakoids). The level of the major light-harvesting complex was completely unaffected by the light quality. In contrast, the quantities of the chlorophyll a-protein complexes of the core antenna, CP43 and CP47 (and probably CP29), changed, with kinetics similar to those of total photosynthetic activity. We postulate that the function of the PSII antenna became increasingly impaired in the absence of blue light (i.e. in red light), while blue light had a restoring effect. The peripheral antenna, comprising the light-harvesting complexes, is probably functionally connected with the reaction-centre chlorophylls via the core antenna chlorophyll-protein complexes (CP43, CP47 and probably CP29). A deficiency of these complexes would lead to uncoupling of antenna and reaction centre in the majority of PSII complexes after long periods of red-light treatment.

show abstract

“…When oxygen evolution is inhibited, the reaction is blocked, and z'!" is rereduced by either endo~enous reductants or by exogenous ~lectron donors in a reaction which typically occurs in the 10 ms 1 s time range [7,8].…”

Section: Discussionmentioning

confidence: 99%

Similarity of EPR Signal IIf rise and P-680+ decay kinetics in Tris-washed chloroplast Photosystem II preparations as a function of pH

Boska

Sauer

Buttner

et al. 1983

Biochimica et Biophysica Acta (BBA) - Bioenergetics

Self Cite

View full text Add to dashboard Cite

Photosystem II oxidation of charged electron donors. Surface charge effects

Cited by 64 publications

References 15 publications

Experimental Evidence for Ascorbate-Dependent Electron Transport in Leaves with Inactive Oxygen-Evolving Complexes

Experimental Evidence for Ascorbate-Dependent Electron Transport in Leaves with Inactive Oxygen-Evolving Complexes

Quantitative correlation of peripheral and intrinsic core polypeptides of photosystem II with photosynthetic electron-transport activity ofAcetabularia mediterranea in red and blue light

Similarity of EPR Signal IIf rise and P-680+ decay kinetics in Tris-washed chloroplast Photosystem II preparations as a function of pH

Contact Info

Product

Resources

About