The structure of the 2[4Fe–4S] ferredoxin from Pseudomonas aeruginosa at 1.32-Å resolution: comparison with other high-resolution structures of ferredoxins and contributing structural features to reduction potential values

Giastas, Petros; Pinotsis, Nikos; Efthymiou, Georgios; Wilmanns, Matthias; Kyritsis, Panayotis; Moulis, Jean‐Marc; Mavridis, Irene M.

doi:10.1007/s00775-006-0094-9

Cited by 37 publications

(28 citation statements)

References 70 publications

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“…The Y501F/ T525A double mutation lowers E m to −128 ± 9 mV. These decreases in the midpoint potentials are consistent with prior observations that hydrogen bonds to cysteine Sγ of cluster ligands tune the redox behavior of the cluster (8,(33)(34)(35)(36). For example, the deletion of residues that are hydrogen bonded to cysteine Sγ lowered the midpoint potentials in R. sphaeroides and Saccharomyces cerevisiae Rieske protein, which is attributed to a decrease in charge density around the sulfur atoms (8,33).…”

Section: Potentiometric Titrationsupporting

confidence: 90%

Impact of Mutations on the Midpoint Potential of the [4Fe-4S]^+1,+2 Cluster and on Catalytic Activity in Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO)

Usselman

Fielding²,

Frerman

et al. 2007

Biochemistry

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Electron transfer flavoprotein -ubiquinone oxidoreductase (ETF-QO) is an iron-sulfur flavoprotein that accepts electrons from electron-transfer flavoprotein (ETF) and reduces ubiquinone from the Q-pool. ETF-QO contains a single [4Fe-4S] 2+,1+ cluster and one equivalent of FAD, which are diamagnetic in the isolated oxidized enzyme and can be reduced to paramagnetic forms by enzymatic donors or dithionite. Mutations were introduced by site-directed mutagenesis of amino acids in the vicinity of the iron-sulfur cluster of Rhodobacter sphaeroides ETF-QO. Y501 and T525 are equivalent to Y533 and T558 in the porcine ETF-QO. In the porcine protein, these residues are within hydrogen bonding distance of the Sγ of the cysteine ligands to the iron-sulfur cluster. Y501F, T525A, and Y501F/T525A substitutions were made to determine the effects on midpoint potential, activity, and EPR spectral properties of the cluster. The integrity of the mutated proteins was confirmed by optical spectra, EPR g-values, and spin-lattice relaxation rates, and the cluster to flavin point-dipole distance was determined by relaxation enhancement. Potentiometric titrations were monitored by changes in the CW EPR signals of the cluster and semiquinone. Single mutations decreased the mid-point potentials of the iron-sulfur cluster from +37 mV for wild type to −60 mV for Y501F and T525A and to −128 mV for Y501F/T525A. Lowering the midpoint potential resulted in a decrease in steady-state ubiquinone reductase activity and in ETF semiquinone disproportionation. The decrease in activity demonstrates that reduction of the iron-sulfur cluster is required for activity. There was no detectable effect of the mutations on the flavin midpoint potentials.Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a monotopic protein that is located in the inner mitochondrial membrane (1). ETF-QO is the electron acceptor for electron transfer flavoprotein (ETF) which catalyzes the oxidation of nine flavoprotein dehydrogenases and two N-methyl dehydrogenases (2, 3). Ubiquinone is the physiological electron acceptor for ETF-QO and transfers the electrons to cytochrome bc 1 complex (Complex III). ETF-QO is essential for the oxidation of fatty acids and some amino acids (1,3,4). Inherited deficiencies of this protein result in a severe metabolic disease known as multiple acyl-CoA dehydrogenase deficiency or glutaric academia type II (5). Interest in the † This work was supported by the National Institutes of Health NIBIB EB002807 (GRE and SSE), The Children's Hospital Research Foundation, Denver, CO (FEF), and by the BBRSC Underwood Fund (NW). * Corresponding author: Prof. Sandra S. Eaton, Department of Chemistry and Biochemistry, Denver, CO 80208-2436, Phone: 303-871-3102, Fax: 303-871-2254 NIH Public Access Author ManuscriptBiochemistry. Author manuscript; available in PMC 2011 May 26. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript pathophysiology of this metabolic disease and the role of the enzyme in oxidative metab...

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Section: Potentiometric Titrationsupporting

confidence: 90%

Impact of Mutations on the Midpoint Potential of the [4Fe-4S]^+1,+2 Cluster and on Catalytic Activity in Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO)

Usselman

Fielding²,

Frerman

et al. 2007

Biochemistry

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“…Indeed, the cysteine ligand pattern is somewhat similar to that observed in some bacterial 2[4Fe-4S] ferredoxins where the two clusters have very different redox potentials[78]. Other idiosyncrasies of M2a sequences concern the H domain, in particular TSCCCPMW as an L1 ligand pattern.…”

mentioning

confidence: 86%

[FeFe] hydrogenases and their evolution: a genomic perspective

Meyer

2007

Cell. Mol. Life Sci.

208

236

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Most hydrogenases (H2ases), the enzymes that produce or oxidize dihydrogen, possess dimetallic active sites and belong to either one of two phylogenetically distinct classes, the [NiFe] and the [FeFe] H2ases. These families of H2ases share a number of similarities regarding active site structure and reaction mechanism, as a result of convergent evolution. They are otherwise alien to each other, in particular with respect to protein sequence and structure, maturation mechanisms, and distribution among the realms of life. One of the interesting features of [FeFe] H2ases is their occurrence in anaerobic bacteria, anaerobic protists, and mitochondriate eukaryotes. They thus have the potential to report on important evolutionary events, including transitions from the prokaryote to the eukaryote lifestyle. Genome sequences yield a variety of [FeFe] H2ase sequences that have been implemented to shed light on the evolution of these proteins and their host organisms.

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“…Reasons for such low potentials are solventshielding of the clusters, side-chain features, cavity sizes and N-H⅐⅐⅐S hydrogen bonds (48). For instance, a bulky amino acid (e.g.…”

Section: Purification and Reconstitution Of The [Fe-s] Clustermentioning

confidence: 99%

X-ray Structure of the Complete ABC Enzyme ABCE1 from Pyrococcus abyssi

Karcher

Schele

Hopfner

2008

Journal of Biological Chemistry

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The ATP binding cassette enzyme ABCE1 (also known as RNase-L (ribonuclease L) inhibitor, Pixie,and HP68), one of the evolutionary most sequence-conserved enzymes, functions in translation initiation, ribosome biogenesis, and human immunodeficiency virus capsid assembly. However, its structural mechanism and biochemical role in these processes have not been revealed. We determined the crystal structure of Pyrococcus abyssi ABCE1 in complex with Mg 2؉ and ADP to 2.8 Å resolution. ABCE1 consists of four structural domains. Two nucleotide binding domains are arranged in a head-to-tail orientation by a hinge domain, suggesting that these domains undergo the characteristic tweezers-like powerstroke of ABC enzymes. In contrast to all other known ABC enzymes, ABCE1 has a N-terminal iron-sulfur-cluster (FeS) domain. The FeS domain contains two [4Fe-4S] clusters and is structurally highly related to

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The structure of the 2[4Fe–4S] ferredoxin from Pseudomonas aeruginosa at 1.32-Å resolution: comparison with other high-resolution structures of ferredoxins and contributing structural features to reduction potential values

Cited by 37 publications

References 70 publications

Impact of Mutations on the Midpoint Potential of the [4Fe-4S]^+1,+2 Cluster and on Catalytic Activity in Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO)

Impact of Mutations on the Midpoint Potential of the [4Fe-4S]^+1,+2 Cluster and on Catalytic Activity in Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO)

[FeFe] hydrogenases and their evolution: a genomic perspective

X-ray Structure of the Complete ABC Enzyme ABCE1 from Pyrococcus abyssi

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The structure of the 2[4Fe–4S] ferredoxin from Pseudomonas aeruginosa at 1.32-Å resolution: comparison with other high-resolution structures of ferredoxins and contributing structural features to reduction potential values

Cited by 37 publications

References 70 publications

Impact of Mutations on the Midpoint Potential of the [4Fe-4S]+1,+2 Cluster and on Catalytic Activity in Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO)

Impact of Mutations on the Midpoint Potential of the [4Fe-4S]+1,+2 Cluster and on Catalytic Activity in Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO)

[FeFe] hydrogenases and their evolution: a genomic perspective

X-ray Structure of the Complete ABC Enzyme ABCE1 from Pyrococcus abyssi

Contact Info

Product

Resources

About

Impact of Mutations on the Midpoint Potential of the [4Fe-4S]^+1,+2 Cluster and on Catalytic Activity in Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO)

Impact of Mutations on the Midpoint Potential of the [4Fe-4S]^+1,+2 Cluster and on Catalytic Activity in Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO)