Crystal structure of chloroplast cytochrome freveals a novel cytochrome fold and unexpected heme ligation

Martinez, Sergio E.; Huang, D.; Szczepaniak, Andrzej; Cramer, William A.; Smith, Janet L.

doi:10.1016/s0969-2126(00)00012-5

Cited by 314 publications

(323 citation statements)

References 46 publications

(50 reference statements)

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“…The spectroscopic results presented here for the cytochrome [24], cytochrome f (His/N-terminal amine) [25], and the butylb560 of bovine SQR complement those obtained previously for amine adduct ofleghemoglobin [19]. Alkaline cytochrome c has the cytochrome b components of B. subtilis and E. coli SQR 2cx = 1480 nm with Ae = 420 M -~ "cm -I (4.2 K and 5 T) [26], [16,17].…”

Section: K and 5 T) In Sqr And Is Broadened And Shifted To 1535supporting

confidence: 81%

Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Crouse¹,

Yu²,

Johnson³

1995

FEBS Letters

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13 kDa), but are devoid of a b-type cytochrome [7]. The QPs Abstract The axial ligands of low potential cytochrome b560 in in SQRs from bovine heart mitochondria [8,9] and E. coli the five subunit bovine heart succinate-ubiquinone reductase com- [10,11] both contain one cytochrome b, but differ in the number plex and in the isolated quinone binding proteins have been invesand size of the constituent subunits (14-, 11-and 9-kDa subtigated using EPR and near-infrared magnetic circular dichroism spectroscopies. The results are consistent with bis-histidine ligaunits for bovine heart QPs [3,4]; 14-and 13-kDa subunits for tion with near-perpendicular imidazole rings for cytochrome b56oE. coli QPs [12,13]). Moreover, the cytochrome bs in these in the four-subunit complex. The pronounced changes in EPR enzymes differ greatly in their midpoint potentials; E m = +36 properties that accompany isolation of the cytochrome-b560 conmV and -180 mV for E. coli and bovine heart SQR, However, this was before the presence of distinct low and high Bovine heart succinate-quinone reductase (SQR) is a mempotential hemes was established in B. subtilis cytochrome b558 brane-bound component of the mitochondrial respiratory [14]. Therefore, although these results taken together attest to chain. It catalyzes the oxidation of succinate to fumarate and bis-histidyl ligation for the high potential cytochrome bs (charthe reduction of ubiquinone, thereby contributing electrons acterized by HALS EPR signals with ramped line shapes for ultimately to oxidative phosphorylation and energy transducthe low-field component), the axial ligation of the low potential tion. The purified complex can be resolved into two reconstitucytochrome bs remains ill-defined. The low potential cytotively active fractions [1,2]. One fraction, composed of the two chrome b560 of bovine heart SQR exhibits a HALS-type EPR larger subunits (70 and 27 kDa), is the soluble succinate dehysignal with a Gaussian-shaped low-field component at g = 3.46, drogenase (SDH) which contains a flavin moiety as well as but this resonance is replaced by two new resonances with low three Fe-S clusters. The other fraction, termed the quinone field g-values at 3.07 and 2.92 in purified QPs [8]. In this work, binding proteins (QPs), anchors SDH to the mitochondrial the two complementary techniques of EPR and MCD have inner membrane and comprises three smaller subunits (14, 11, been used to investigate the axial ligation of the low potential and 9 kDa) [3,4]. This membrane-bound fraction contains the cytochrome b560 in bovine heart SQR and the isolated QPs. cytochrome b560 that is the focus of this paper [5,6].As their name suggests, the QPs facilitate interaction of 2. Materials and methods SDHs and the highly homologous fumarate reductases (FRDs) with quinones. However, a specific role for the heme group in Bovine heart SQR and QPs were purified and assayed as previously mediating electron transfer to or from quinone has yet to be described [8]. Samples for spectroscopic measurements were prepar...

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Section: K and 5 T) In Sqr And Is Broadened And Shifted To 1535supporting

confidence: 81%

Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Crouse¹,

Yu²,

Johnson³

1995

FEBS Letters

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“…Modifications of the Hinge and Vise that Affect TurnoVer of the bc 1 Complex. Several lines of evidence have suggested that modification of the vise region or hinge might affect reactions at the Q o site.…”

Section: Mobility and Binding Of The Isp: Complementary Functional Asmentioning

confidence: 99%

“…The ubihydroquinone:cytochrome c oxidoreductase (bc 1 complex) 1 (E.C. 1.10.2.2) and the related b 6 f complex of oxygenic photosynthesis are central components of the major electron-transfer chains that carry the energy flux of the biosphere.…”

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confidence: 99%

Mechanism of Ubiquinol Oxidation by the bc₁ Complex: Role of the Iron Sulfur Protein and Its Mobility

et al. 1999

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Native structures of ubihydroquinone:cytochrome c oxidoreductase (bc 1 complex) from different sources, and structures with inhibitors in place, show a 16-22 Å displacement of the [2Fe-2S] cluster and the position of the C-terminal extrinsic domain of the iron sulfur protein. None of the structures shows a static configuration that would allow catalysis of all partial reactions of quinol oxidation. We have suggested that the different conformations reflect a movement of the subunit necessary for catalysis. The displacement from an interface with cytochrome c 1 in native crystals to an interface with cytochrome b is induced by stigmatellin or 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole (UHDBT) and involves ligand formation between His-161 of the [2Fe-2S] binding cluster and the inhibitor. The movement is a rotational displacement, so that the same conserved docking surface on the iron sulfur protein interacts with cytochrome c 1 and with cytochrome b. The mobile extrinsic domain retains essentially the same tertiary structure, and the anchoring N-terminal tail remains in the same position. The movement occurs through an extension of a helical segment in the short linking span. We report details of the protein structure for the two main configurations in the chicken heart mitochondrial complex and discuss insights into mechanism provided by the structures and by mutant strains in which the docking at the cytochrome b interface is impaired. The movement of the iron sulfur protein represents a novel mechanism of electron transfer, in which a tethered mobile head allows electron transfer through a distance without the entropic loss from free diffusion.The ubihydroquinone:cytochrome c oxidoreductase (bc 1 complex) 1 (E.C. 1.10.2.2) and the related b 6 f complex of oxygenic photosynthesis are central components of the major electron-transfer chains that carry the energy flux of the biosphere. The bc 1 complex of the mitochondrial respiratory chain transfers electrons from ubihydroquinone (quinol) to cytochrome (cyt) c in the aqueous phase and catalyzes the coupled transfer of protons across the membrane. Our understanding of the function of these enzymes at the atomic level has been greatly aided by structures recently solved by X-ray crystallography. These include cyt f (the equivalent of cyt c 1 in the b 6 f complex) from chloroplasts (1, 2) and the Rieske iron sulfur protein (ISP) from the beef heart mitochondrial complex (3) and chloroplasts (4), all crystallized as water-soluble fragments generated by proteolysis or mutagenesis. A partial structure of the beef heart mitochondrial complex at ∼2.9 Å resolution has been published by Xia and colleagues (5, 6). However, the crystals were disordered in the region of the ISP and cytochrome c 1 , and this precluded a detailed consideration of the mechanistic role of these subunits. More complete structures for the complexes from chicken, rabbit, and beef heart mitochondria have been provided by Zhang et al. ‡ University of Illinois. § University of California. ...

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“…In addition, the positions of the heme domains, in particular the distances between the heme-irons of each monomer and the orientations of the cyt c 1 and cyt f heme planes are also dissimilar, with the former being almost perpendicular to the membrane, and the latter at a 25-30° angle from it ( (Kurisu et al 2003;Stroebel et al 2003)). Finally, although one axial ligand of the heme is His in both cyts, the other axial ligand is Met in cyt c 1 while the NH 2 group of the N-terminus plays this role in cyt f ( (Martinez et al 1994)). …”

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confidence: 99%

X-Ray Structure of Rhodobacter Capsulatus Cytochrome bc₁: Comparison with its Mitochondrial and Chloroplast Counterparts

Berry

Huang

Saechao

et al. 2004

Photosynthesis Research

198

217

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Crystal structure of chloroplast cytochrome freveals a novel cytochrome fold and unexpected heme ligation

Cited by 314 publications

References 46 publications

Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Mechanism of Ubiquinol Oxidation by the bc₁ Complex: Role of the Iron Sulfur Protein and Its Mobility

X-Ray Structure of Rhodobacter Capsulatus Cytochrome bc₁: Comparison with its Mitochondrial and Chloroplast Counterparts

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Crystal structure of chloroplast cytochrome freveals a novel cytochrome fold and unexpected heme ligation

Cited by 314 publications

References 46 publications

Spectroscopic identification of the axial ligands of cytochrome b560 in bovine heart succinate‐ubiquinone reductase

Spectroscopic identification of the axial ligands of cytochrome b560 in bovine heart succinate‐ubiquinone reductase

Mechanism of Ubiquinol Oxidation by the bc1 Complex: Role of the Iron Sulfur Protein and Its Mobility

X-Ray Structure of Rhodobacter Capsulatus Cytochrome bc1: Comparison with its Mitochondrial and Chloroplast Counterparts

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Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Spectroscopic identification of the axial ligands of cytochrome b₅₆₀ in bovine heart succinate‐ubiquinone reductase

Mechanism of Ubiquinol Oxidation by the bc₁ Complex: Role of the Iron Sulfur Protein and Its Mobility

X-Ray Structure of Rhodobacter Capsulatus Cytochrome bc₁: Comparison with its Mitochondrial and Chloroplast Counterparts