A membrane-bound monoheme cytochrome c551 of a novel type is the immediate electron donor to P840 of the Chlorobium vibrioforme photosynthetic reaction center complex.

Okkels, Jens Sigurd; Kjær, Bodil; Hansson, Örjan; Svendsen, Ib; Møller, B L; Scheller, Henrik Vibe

doi:10.1016/s0021-9258(19)36808-5

Cited by 85 publications

(41 citation statements)

References 41 publications

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“…It is also similar to the chemically-reduced-minus-oxidized difference spectrum of P840 ϩ /P840, measured in the same sample (Fig. 3 a) and in a similar RC preparation from Chlorobium vibrioforme (Okkels et al, 1992).…”

Section: Discussionsupporting

confidence: 84%

“…Chlorobium vibrioforme strain NCIB 8327 was grown as previously described (Okkels et al, 1992), and the RCCs were prepared using n-dodecyl-␤-D-maltoside (␤-DM) to solubilize the membranes under strict anaerobic conditions (Kjaer et al, 1994). The final step in the isolation utilized gel-filtration chromatography, and several fractions from the column were collected.…”

Section: Isolation Of the Rcc Complexesmentioning

confidence: 99%

“…A number of kinetic studies of P840 were made using transient absorbance spectroscopy at wavelengths around 835-840 nm (Miller et al, 1992;Okkels et al, 1992;Francke et al, 1997;Neerken et al, 1998;Schmidt et al, 2000), where a bleaching of Bchl occurs. Transient absorbance spectra of RC preparations from different green sulfur bacteria have been measured in the near-infrared (NIR) at wavelengths up to 900 nm (Kramer et al, 1996;Oh-Oka et al, 1995a,b).…”

Section: Introductionmentioning

confidence: 99%

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Photoinduced Transient Absorbance Spectra of P840/P840+ and the FMO Protein in Reaction Centers of Chlorobium vibrioforme

Vassiliev

Kjær²,

Schorner

et al. 2001

Biophysical Journal

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The kinetics of photoinduced absorbance changes in the 400-ns to 100-ms time range were studied between 770 and 1025 nm in reaction center core (RCC) complexes isolated from the green sulfur bacterium Chlorobium vibrioforme. A global, multiple stretched-exponential analysis shows the presence of two distinct but strongly overlapping spectra. The spectrum of the 70-micros component consists of a broad bleaching with two minima at 810 and 825 nm and a broad positive band at wavelengths greater than 865 nm and is assigned to the decay of (3)Bchl a of the Fenna-Matthews-Olson (FMO) protein. The contribution of the 70-micros component correlates with the amount of FMO protein in the isolated RCC complex. The spectrum of the 1.6-micros component has a sharp bleaching at 835 nm, a maximum at 805 nm, a broad positive band at wavelengths higher than 865 nm, and a broad negative band at wavelengths higher than 960 nm. When the RCC is incubated with inorganic iron and sulfur, the 1.6-micros component is replaced by a component with a lifetime of approximately 40 micros, consistent with the reconstruction of the F(X) cluster. We propose that the 1.6-micros component results from charge recombination between P840(+) and an intermediate electron acceptor operating between A(0) and F(X). Our studies in Chlorobium RCCs show that approaches that employ a single wavelength in the measurement of absorption changes have inherent limitations and that a global kinetic analysis at multiple wavelengths in the near-infrared is required to reliably separate absorption changes due to P840/P840(+) from the decay of (3)Bchl a in the FMO protein.

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Section: Discussionsupporting

confidence: 84%

Section: Isolation Of the Rcc Complexesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photoinduced Transient Absorbance Spectra of P840/P840+ and the FMO Protein in Reaction Centers of Chlorobium vibrioforme

Vassiliev

Kjær²,

Schorner

et al. 2001

Biophysical Journal

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“…A 32-kDa cytochrome with an R band at 553 nm was shown to copurify with the RC of Chlorobium (C.) limicola after mild solubilization of the membranes (Feiler et al, 1992). Okkels et al (1992) reported that an 18-kDa cytochrome c 551 copurifies with the RC from Chlorobium Vibrioforme and that no other cytochrome was found associated with the RC. From the gene sequence of this cytochrome, it could be concluded that it possesses only one heme binding site, and no homologies to other known cytochromes, in particular to the RC-associated tetraheme cytochromes from purple bacteria, could be found.…”

mentioning

confidence: 99%

“…Biphasic kinetics were measured for both the reduction of P 840 + and photooxidation of this cytochrome, in agreement with those previously reported by Prince and Olson (1976) on cytochrome c 553 from C. limicola. The biphasic kinetics were interpreted by Okkels et al (1992) as resulting from distinct conformations of the cytochrome/RC complex. c-type cytochromes with R bands between 550.5 and 551 nm and apparent molecular masses from 21 to 24 kDa have also been observed in different RC preparations from C. limicola and Chlorobium tepidum (Hurt & Hauska, 1984;Oh-oka et al, 1993Oh-oka et al, , 1995Kusumuto et al, 1994).…”

mentioning

confidence: 99%

Membrane-Associated c-type Cytochromes from the Green Sulfur Bacterium Chlorobium limicola forma thiosulfatophilum: Purification and Characterization of Cytochrome c₅₅₃

et al. 1997

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Tetraheme cytochromes involved in photosynthetic electron transport have previously been described associated with the reaction centers of purple photosynthetic bacteria; however, similar heme proteins have not until now been characterized in the phylogenetically distinct green sulfur bacteria. In this paper we describe the first isolation and characterization of a multitheme, membrane-associated cytochrome from a green sulfur bacterium, Chlorobium limicola forma thiosulfatophilum. We show that this cytochrome contains a single polypeptide of 32 kDa apparent molecular mass on SDS-PAGE and has a characteristic broad alpha-band absorption at 553 nm. By both low-temperature absorption and electron paramagnetic resonance spectroscopy, we demonstrate that there are at least four distinct heme groups.

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A novel membrane-associated c-type cytochrome, cyt cy, can mediate the photosynthetic growth of Rhodobacter capsulatus and Rhodobacter sphaeroides.

1993

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Mutants of Rhodobacter capsulatus lacking the soluble electron carrier cytochrome c2 are able to grow photosynthetically (Ps+), whereas Rhodobacter sphaeroides is unable to do so. To understand this unusual electron transfer pathway the gene required for cyt c2‐independent growth of R.capsulatus was sought using chromosomal libraries derived from a cyt c2‐ mutant of this species to complement a Ps‐ cyt c2‐ mutant of R.sphaeroides to Ps+ growth. The complementing 1.2 kbp DNA fragment contained a gene, cycY, encoding a novel membrane‐associated c‐type cytochrome, cyt cy, based on predicted amino acid sequence, optical difference spectra and SDS‐PAGE analysis of chromatophore membranes. The predicted primary sequence of cyt cy is unusual in having two distinct domains, a hydrophobic amino‐terminal region and a carboxyl‐terminus with strong homology to cytochromes c. A cyt cy‐ mutant of R.capsulatus remains Ps+ as does the cyt c2‐ mutant. However, a mutant lacking both cyt c2 and cy is Ps‐, and can be complemented to Ps+ by either cyt c2 or cyt cy. These findings demonstrate that each of the cytochromes c2 and cy is essential for photosynthesis only in the absence of the other. Thus, two distinct electron transfer pathways, unrecognized until now, operate during photosynthesis in R.capsulatus under appropriate conditions, one via the soluble cyt c2 and the other via the membrane‐associated cyt cy.

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A membrane-bound monoheme cytochrome c551 of a novel type is the immediate electron donor to P840 of the Chlorobium vibrioforme photosynthetic reaction center complex.

Cited by 85 publications

References 41 publications

Photoinduced Transient Absorbance Spectra of P840/P840+ and the FMO Protein in Reaction Centers of Chlorobium vibrioforme

Photoinduced Transient Absorbance Spectra of P840/P840+ and the FMO Protein in Reaction Centers of Chlorobium vibrioforme

Membrane-Associated c-type Cytochromes from the Green Sulfur Bacterium Chlorobium limicola forma thiosulfatophilum: Purification and Characterization of Cytochrome c₅₅₃

A novel membrane-associated c-type cytochrome, cyt cy, can mediate the photosynthetic growth of Rhodobacter capsulatus and Rhodobacter sphaeroides.

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A membrane-bound monoheme cytochrome c551 of a novel type is the immediate electron donor to P840 of the Chlorobium vibrioforme photosynthetic reaction center complex.

Cited by 85 publications

References 41 publications

Photoinduced Transient Absorbance Spectra of P840/P840+ and the FMO Protein in Reaction Centers of Chlorobium vibrioforme

Photoinduced Transient Absorbance Spectra of P840/P840+ and the FMO Protein in Reaction Centers of Chlorobium vibrioforme

Membrane-Associated c-type Cytochromes from the Green Sulfur Bacterium Chlorobium limicola forma thiosulfatophilum: Purification and Characterization of Cytochrome c553

A novel membrane-associated c-type cytochrome, cyt cy, can mediate the photosynthetic growth of Rhodobacter capsulatus and Rhodobacter sphaeroides.

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Membrane-Associated c-type Cytochromes from the Green Sulfur Bacterium Chlorobium limicola forma thiosulfatophilum: Purification and Characterization of Cytochrome c₅₅₃