Purification and characterization of cytochrome c 6 from Acaryochloris marina

Bell, Patrick; Xin, Yueyong; Blankenship, Robert E.

doi:10.1007/s11120-009-9482-7

Cited by 7 publications

(1 citation statement)

References 29 publications

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“…Redox Potentiometry. The midpoint redox potentials of the heme cofactors of ACIII were determined using an optically transparent thin film electrode along with a potentiostat, and the data were analyzed by a method previously described (35). Although ACIII has more than one type of redox unit (e.g., heme and iron-sulfur cluster) functioning as electron transfer centers, in this method the c type hemes were selectively assayed spectrally as a function of potential.…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2010

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The green photosynthetic bacterium Chloroflexus aurantiacus, which belongs to the phylum of filamentous anoxygenic phototrophs, does not contain a cytochrome bc or bf type complex as is found in all other known groups of phototrophs. This suggests that a functional replacement exists to link the reaction center photochemistry to cyclic electron transfer as well as respiration. Earlier work identified a potential substitute of the cytochrome bc complex, now named alternative complex III (ACIII), which has been purified, identified and characterized from C. aurantiacus. ACIII functions as a menaquinol:auracyanin oxidoreductase in the photosynthetic electron transfer chain, and a related but distinct complex functions in respiratory electron flow to a terminal oxidase. In this work, we focus on elucidating the structure of the photosynthetic ACIII. We found that AC III is an integral-membrane protein complex of around 300 kDa that consists of 8 subunits of 7 different types. Among them, there are 4 metalloprotein subunits, including a 113 kDa ironsulfur cluster-containing polypeptide, a 25 kDa penta-heme c-containing subunit and two 20 kDa mono-heme c-containing subunits in the form of a homodimer. A variety of analytical techniques were employed in determining the ACIII substructure, including HPLC combined with ESI-MS, metal analysis, potentiometric titration and intensity analysis of heme-staining SDS-PAGE. A preliminary structural model of the ACIII complex is proposed based on the analytical data and chemical cross-linking in tandem with mass analysis using MALDI-TOF, as well as transmembrane and transit peptide analysis.Bacterial electron transport pathways largely fall into two major categories: the light-driven photosynthetic electron transfer chain and the aerobic or anaerobic respiratory electron transfer chain. Despite the vast differences between photo-and oxidative phosphorylations, they both couple the chemical reactions between electron donors and electron accepters to the translocation of protons across the membrane, which then drives ATP formation and other energy-dependent processes (1). As a result, the common feature of all electron transport chains is the presence of a proton pump to create the transmembrane proton gradient. In respiratory electron transfer pathways, there may be as many as three types of proton pumping protein complexes reminiscent of mitochondria, depending on * Address correspondence to: Robert E. Blankenship, Washington University in St. Louis, One Brookings Dr., CB 1137, St. Louis, . blankenship@wustl.edu. Supporting information available The identification of the cross-linked products. This supplementary material is available free of charge via the internet at http://pubs.acs.org. NIH Public Access Author ManuscriptBiochemistry. Author manuscript; available in PMC 2011 August 10. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript environmental factors (2). In contrast, the proton pump in all the photosynthetic electron transfer chains was u...

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Section: Resultsmentioning

confidence: 99%

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

et al. 2010

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The Diversity of Photosynthetic Cytochromes

Majumder¹,

Blankenship²

2016

Advances in Photosynthesis and Respiration

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Chlorophyll d and Acaryochloris marina: current status

2013

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The discovery of the chlorophyll d-containing cyanobacterium Acaryochloris marina in 1996 precipitated a shift in our understanding of oxygenic photosynthesis. The presence of the red-shifted chlorophyll d in the reaction centre of the photosystems of Acaryochloris has opened up new avenues of research on photosystem energetics and challenged the unique status of chlorophyll a in oxygenic photosynthesis. In this review, we detail the chemistry and role of chlorophyll d in photosynthesis and summarise the unique adaptations that have allowed the proliferation of Acaryochloris in diverse ecological niches around the world.

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Purification and characterization of cytochrome c 6 from Acaryochloris marina

Cited by 7 publications

References 29 publications

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

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

The Diversity of Photosynthetic Cytochromes

Chlorophyll d and Acaryochloris marina: current status

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