Photosynthesis of ATP—Electrons, Proton Pumps, Rotors, and Poise

  title={Photosynthesis of ATP—Electrons, Proton Pumps, Rotors, and Poise},
  author={John F. Allen},

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Cyclic electron transport around photosystem I: genetic approaches.

  • T. Shikanai
  • Environmental Science
    Annual review of plant biology
  • 2007
It is necessary to reconsider the fundamental mechanisms of chloroplast energetics and clarify the essential functions of this electron flow in both photoprotection and photosynthesis.

Plants Increase Photosynthesis Efficiency by Lowering the Proton Gradient across the Thylakoid Membrane

In chloroplasts, the pigments of the light-harvesting complex channel light energy to PSII and PSI. The light energy is used to separate an electron from PSII, starting its cascade through the

Integrating the proton circuit into photosynthesis: progress and challenges

The formation of trans-thylakoid proton motive force (pmf) is coupled to light-driven electron transfer and both powers the synthesis of ATP and acts as a signal for initiating antenna regulation.

Regulating the proton budget of higher plant photosynthesis.

In vivo probes of the proton circuit in wild-type and a mutant strain of Arabidopsis thaliana show that regulation of light capture is modulated primarily by altering the resistance of proton efflux from the thylakoid lumen, whereas modulation of propton influx through cyclic electron flow around photosystem I is suggested to play a role in regulating the ATP/NADPH output ratio of the light reactions.

Regulatory network of proton motive force: contribution of cyclic electron transport around photosystem I

This mechanism sacrifices homeostasis of the thylakoid lumen pH, seriously disturbing the pH-dependent regulation of photosynthetic electron transport, induction of qE, and downregulation of the cytochrome b6f complex.

Cyclic electron flow around photosystem I is essential for photosynthesis

Evidence that cyclic flow is essential for efficient photosynthesis is presented, by constructing mutants in Arabidopsis thaliana in which both PSI cyclic pathways are impaired, and present evidence that linear flow from water to NADP+ is commonly used.

Functions of REP27 and the low molecular weight proteins PsbX and PsbW in repair and assembly of photosystem II

Oxygenic photosynthesis is the major producer of both oxygen and organic compounds on earth and takes place in plants, green algae and cyanobacteria. The thylakoid membranes are the site of the ...




A critical evaluation of the evidence in support of and against the notion that one part of the enzyme rotates with respect to other parts during catalytic turnover concludes that although rotation can occur, whether it is required for activity of the ATP synthase has not been established unequivocally.

Structural biology: Proton-powered turbine of a plant motor

This work has imaged the ATP synthase from leaf chloroplasts by using atomic force microscopy and, surprisingly, finds that its turbine has 14 subunits, arranged in a cylindrical ring.

Concerning a dual function of coupled cyclic electron transport in leaves.

Coupled cyclic electron transport is assigned a role in the protection of leaves against photoinhibition in addition to its role in ATP synthesis and avoidance of overreduction of the electron transport chain is a prerequisite for the efficient protection of the photosynthetic apparatus against photo inactivation.

Molecular mechanisms of photosynthesis

This chapter discusses the organization and structure of Photosynthetic Systems, as well as the history and development of Photosynthesis, and the origins and evolution of photosynthesis.

Photosynthetic control of chloroplast gene expression

Here it is shown that the redox state of plastoquinone also controls the rate of transcription of genes encoding reaction-centre apoproteins of photosystem I and photosystem II, and the stoichiometry between the two photosystems changes in a way that counteracts the inefficiency produced when either photosystem limits the rates of the other.

A quantitative model of the domain structure of the photosynthetic membrane.

Involvement of state transitions in the switch between linear and cyclic electron flow in Chlamydomonas reinhardtii

The results demonstrate that the transition from state 1 to state 2 induces a switch from linear to cyclic electron flow in this alga and reveal a strict cause–effect relationship between the redistribution of antenna complexes during state transitions and the onset of cyclic electrons flow.

Photosynthesis by Isolated Chloroplasts

Evidence is given for the action of the photochemically generated assimilatory power on two phases of the reductive carbohydrate cycle in isolated chloroplasts: the carboxylative phase which includes the phosphorylation of ribulose monophosphate and the fixation of COZ, and the reduction of 3-phosphoglyceric acid and the formation of hexose phosphate.

Molecular recognition in thylakoid structure and function.