Structural Analysis of Alternative Complex III in the Photosynthetic Electron Transfer Chain ofChloroflexus aurantiacus

Photosystem II particles that retain the ability to evolve O2 have been used to examine acceptor and inhibitor sites in the photosynthetic electron transfer chain between Q and plastoquinone. Employing the water to dichlorobenzoquinone reaction to assay photosystem II activity, we have demonstrated that electron transport in thylakoids and particles is equally sensitive to inhibition by DCMU. dinoseb, metribuzin, HQNO and DBMIB. Based on differential sensitivity to inhibition by DCMU vs. HQNO or DBMIB, we suggest that when synthetic quinones, e.g. 2,6-dichlorobenzoquinone operate as Hill reagents in particles they are reduced primarily by the plastoquinone pool. When synthetic quinones, e.g. 5,6-methylenedioxy-2,3-dimethyl benzoquinone act as autoxidizable acceptors they accept electron from the Q/B complex at a point that is located between the DCMU and HQNO (DBMIB) inhibition sites.

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Role of the photosynthetic electron transfer chain in electrogenic activity of cyanobacteria

Applied Microbiology and Biotechnology ◽

10.1007/s00253-011-3239-x ◽

2011 ◽

Vol 91 (2) ◽

pp. 377-385 ◽

Cited By ~ 54

Author(s):

John M. Pisciotta ◽

YongJin Zou ◽

Ilia V. Baskakov

Keyword(s):

Electron Transfer ◽

Electron Transfer Chain ◽

Transfer Chain ◽

Photosynthetic Electron Transfer

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Biogenesis of chloroplast membranes X. Changes in the photosynthetic specific activity and the relationship between the light harvesting system and photosynthetic electron transfer chain during greening of Chlamydomonas reinhardi y-1 cells

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/0005-2728(72)90145-4 ◽

1972 ◽

Vol 267 (1) ◽

pp. 138-148 ◽

Cited By ~ 5

Author(s):

S. Bar-Nun ◽

D. Wallach ◽

I. Ohad

Keyword(s):

Electron Transfer ◽

Light Harvesting ◽

Specific Activity ◽

Chloroplast Membranes ◽

Electron Transfer Chain ◽

The Relationship ◽

Transfer Chain ◽

Photosynthetic Electron Transfer

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Chlororespiration

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2000.0714 ◽

2000 ◽

Vol 355 (1402) ◽

pp. 1541-1547 ◽

Cited By ~ 84

Author(s):

Peter J. Nixon

Keyword(s):

Electron Transfer ◽

Thylakoid Membrane ◽

Redox State ◽

Original Model ◽

Current Status ◽

Electrochemical Gradient ◽

Electron Transfer Chain ◽

Plastoquinone Pool ◽

Transfer Chain ◽

Photosynthetic Electron Transfer

The term ‘chlororespiration’ is used to describe the activity of a putative respiratory electron transfer chain within the thylakoid membrane of chloroplasts and was originally proposed by Bennoun in 1982 to explain effects on the redox state of the plastoquinone pool in green algae in the absence of photosynthetic electron transfer. In his original model, Bennoun suggested that the plastoquinone pool could be reduced through the action of a NAD(P)H dehydrogenase and could be oxidized by oxygen at an oxidase. At the same time an electrochemical gradient would be generated across the thylakoid membrane. This review describes the current status of the chlororespiration model in light of the recent discoveries of novel respiratory components within the chloroplast thylakoid membrane.

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The crystalline structure in the membranous preparations of mitochondrial complex III

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082327 ◽

1978 ◽

Vol 36 (2) ◽

pp. 292-293

Author(s):

Junpei Asai

Keyword(s):

Electron Transfer ◽

Complex Iii ◽

Molecular Architecture ◽

Membrane Formation ◽

Electron Transfer Chain ◽

Ultrastructural Studies ◽

Mitochondrial Inner Membrane ◽

Beef Heart Mitochondria ◽

The Individual ◽

Transfer Chain

In 1962 Hatefi and his collegues showed biochemically the isolation of four complexes of the electron transfer chain from the mitochondria and the reconstitution of a complete electron transfer chain through re-association of the individual complexes. Tzagoloff et al demonstrated ultrastructurally the membrane formation by either single complex or a mixture of complexs. However, there have been a few direct ultrastructural studies in the molecular architecture of mitochondrial inner membrane. To understand the organization of Complex III (QH2-cytochrome c reductase) in the membrane, the membranes made from this complex under various conditions were examined ultrastructurally in the present study.Complex III was purified from beef heart mitochondria by the method of Heatefi et al as modified by Rieske et al. For the preparations of membrane formation, some samples of the purified complex suspended in the solution contained 0.66 M sucrose were diluted with 100 volumes of the mixture of 0.25 M in sucrose and 0.01 M in Tris-HCl (sucrose-Tris), pH 8.0 and were incubated for 30 min. at 0-4°C.

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