Two Distinct Binding Sites for High Potential Iron-Sulfur Protein and Cytochrome c on the Reaction Center-bound Cytochrome of Rubrivivax gelatinosus

Alric, Jean; Yoshida, Makoto; Nagashima, Kenji V. P.; Hienerwadel, Rainer; Parot, Pierre; Vermeglio, André; Chen, Shu‐wen W.; Pellequer, Jean‐Luc

doi:10.1074/jbc.m401784200

Cited by 9 publications

(11 citation statements)

References 42 publications

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“…Membrane fragments were diluted in 50 mM Mops (pH 7), 130 g͞liter NaCl. Laser flash-induced absorption changes were measured by a laboratory-built spectrophotometer as described (23).…”

Section: Methodsmentioning

confidence: 99%

“…All structural models proposed so far suggest that HiPIP interacts with the outermost heme of the subunit (heme 1 or H1), through its hydrophobic surface (20)(21)(22)(23)(24)(25). Solving the Marcus equation by using an E m value of ϩ140 mV mentioned above for the docked HiPIP II and ϩ60 mV determined for H1 and by adopting the docking geometry assumed by Alric et al (23) for the case of Rubrivivax gelatinosus, we arrive at a t 1/2 for electron transfer of Ϸ11 s. To be able to reproduce the experimentally determined t 1/2 of 300 s in the Rubrivivax gelatinosus case, Alric et al (23) interchanged the previous attribution of E m -values (44) to heme H1 and H4 (the second low potential heme). Stimulated by our results on H. halophila, we determined the E m value of the Rubrivivax gelatinosus HiPIP in its membrane-bound state.…”

Section: Kinetics and Energetics Of The Donation Reaction From Hipip mentioning

confidence: 99%

“…In contrast, the interaction between HiPIP and RC is still poorly understood. Except for the case of Rubrivivax gelatinosus (20)(21)(22)(23), only scarce data are available (24,25). Surveys of photosynthetic electron transfer among proteobacterial species, however, show that the participation of HiPIP instead of soluble cytochrome c is the rule rather than the exception (26).…”

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confidence: 99%

“…Site-directed mutagenesis experiments on the Rubrivivax gelatinosus tetraheme subunit (18,20,21,23) have already indicated that the docking of HiPIP to the cytochrome subunit involved hydrophobic rather than electrostatic interactions as is the case for cytochrome c 2 .…”

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confidence: 99%

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Study of the high-potential iron sulfur protein in Halorhodospira halophila confirms that it is distinct from cytochrome c as electron carrier

Lieutaud

Alric

Bauzan

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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The role of high-potential iron sulfur protein (HiPIP) in donating electrons to the photosynthetic reaction center in the halophilic ␥-proteobacterium Halorhodospira halophila was studied by EPR and time-resolved optical spectroscopy. A tight complex between HiPIP and the reaction center was observed. The EPR spectrum of HiPIP in this complex was drastically different from that of the purified protein and provides an analytical tool for the detection and characterization of the complexed form in samples ranging from whole cells to partially purified protein. The bound HiPIP was identified as iso-HiPIP II. Its Em value at pH 7 in the form bound to the reaction center was Ϸ100 mV higher (؉140 ؎ 20 mV) than that of the purified protein. EPR on oriented samples showed HiPIP II to be bound in a well defined geometry, indicating the presence of specific protein-protein interactions at the docking site. At moderately reducing conditions, the bound HiPIP II donates electrons to the cytochrome subunit bound to the reaction center with a half-time of <11 s. This donation reaction was analyzed by using Marcus's outer-sphere electron-transfer theory and compared with those observed in other HiPIP-containing purple bacteria. The results indicate substantial differences between the HiPIP-and the cytochrome c 2-mediated re-reduction of the reaction center.electron transfer ͉ photosynthesis ͉ electron paramagnetic resonance ͉ redox potential ͉ reaction center H igh-potential iron sulfur proteins (HiPIPs) are soluble electron carriers containing a single cubane [Fe 4 S 4 ] cluster [for reviews, see refs. 1 and 2] found in both photosynthetic (3-6) and nonphotosynthetic (7, 8) proteobacteria, as well as in members of the so-called FBC group (flexibacter, bacteroides, cytophaga group) (9). Despite three decades of detailed biophysical and biochemical characterization, the role of HiPIPs as physiological electron donors to the reaction center (RC) in photosynthesis and to oxidase in respiration was not demonstrated until 1995 (10-12).HiPIPs are commonly regarded as exotic substitutes for the ''normal'' soluble carrier cytochrome c. This notion is based on the presence of soluble cytochromes in mitochondrial respiration, in cyanobacterial photosynthesis, and in a variety of other prokaryotic energy conserving systems. Moreover, the usual ''workhorses'' in the study of purple bacterial photosynthesis, Rhodobacter sphaeroides, Rhodobacter capsulatus, and Blastochloris viridis, do not contain HiPIP. Instead, cytochrome c 2 , together with its various iso-forms, functions in their bioenergetic chains. Several decades of studies on these species have resulted in an understanding of the structural and functional details of electron donation from cytochrome c 2 to the photosynthetic RC (see, for example, refs. 13-19). In contrast, the interaction between HiPIP and RC is still poorly understood. Except for the case of Rubrivivax gelatinosus (20-23), only scarce data are available (24, 25). Surveys of photosynthetic electron transfer among p...

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“…Membrane fragments were diluted in 50 mM Mops (pH 7), 130 g͞liter NaCl. Laser flash-induced absorption changes were measured by a laboratory-built spectrophotometer as described (23).…”

Section: Methodsmentioning

confidence: 99%

Section: Kinetics and Energetics Of The Donation Reaction From Hipip mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Study of the high-potential iron sulfur protein in Halorhodospira halophila confirms that it is distinct from cytochrome c as electron carrier

Lieutaud

Alric

Bauzan

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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“…gelatinosus RC with the Rvi. gelatinosus cytochrome c 8 has also been presented very recently (Alric et al 2004). The model was built by analogy with the complex crystal structure of the yeast cytochrome bc 1 complex with the cytochrome c. It was assumed that the orientation of the heme groups in the cytochrome bc 1 complex and the cytochrome c should be somewhat similar to that in the RC and cytochrome c 8 .…”

Section: Structural Models Of Rc-soluble Electron Carrier Complexesmentioning

confidence: 99%

Structural and functional studies on the tetraheme cytochrome subunit and its electron donor proteins: the possible docking mechanisms during the electron transfer reaction

2005

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The photosynthetic reaction centers (RCs) classified as the group II possess a peripheral cytochrome (Cyt) subunit, which serves as the electron mediator to the special-pair. In the cycle of the photosynthetic electron transfer reactions, the Cyt subunit accepts electrons from soluble electron carrier proteins, and re-reduces the photo-oxidized special-pair of the bacteriochlorophyll. Physiologically, high-potential cytochromes such as the cytochrome c2 and the high-potential iron-sulfur protein (HiPIP) function as the electron donors to the Cyt subunit. Most of the Cyt subunits possess four heme c groups, and it was unclear which heme group first accepts the electron from the electron donor. The most distal heme to the special-pair, the heme-1, has a lower redox potential than the electron donors, which makes it difficult to understand the electron transfer mechanism mediated by the Cyt subunit. Extensive mutagenesis combined with kinetic studies has made a great contribution to our understanding of the molecular interaction mechanisms, and has demonstrated the importance of the region close to the heme-1 in the electron transfer. Moreover, crystallographic studies have elucidated two high-resolution three-dimensional structures for the RCs containing the Cyt subunit, the Blastochloris viridis and Thermochromatium tepidum RCs, as well as the structures of their electron donors. An examination of the structural data also suggested that the binding sites for both the cytochrome c2 and the HiPIP are located adjacent to the solvent-accessible edge of the heme-1. In addition, it is also indicated by the structural and biochemical data that the cytochrome c2 and the HiPIP dock with the Cyt subunit by c2 is recognized through electrostatic interactions while hydrophobic interactions are important in the HiPIP docking.

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Functional Coupling Between Reaction Centers and Cytochrome bc 1 Complexes

Lavergne

Vermeglio

Joliot

2009

The Purple Phototrophic Bacteria

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Two Distinct Binding Sites for High Potential Iron-Sulfur Protein and Cytochrome c on the Reaction Center-bound Cytochrome of Rubrivivax gelatinosus

Cited by 9 publications

References 42 publications

Study of the high-potential iron sulfur protein in Halorhodospira halophila confirms that it is distinct from cytochrome c as electron carrier

Study of the high-potential iron sulfur protein in Halorhodospira halophila confirms that it is distinct from cytochrome c as electron carrier

Structural and functional studies on the tetraheme cytochrome subunit and its electron donor proteins: the possible docking mechanisms during the electron transfer reaction

Functional Coupling Between Reaction Centers and Cytochrome bc 1 Complexes

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