Crystallization and structure determination of 2.5-.ANG. resolution of the oxidized iron-sulfur [2Fe-2S] ferredoxin isolated from Anabaena 7120

Rypniewski, W.; Breiter, Deborah R.; Benning, Matthew M.; Wesenberg, G.E.; Oh, Byung Ha; Markley, John L.; Rayment, Ivan; Holden, Hazel M.

doi:10.1021/bi00231a003

Cited by 190 publications

(146 citation statements)

References 21 publications

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“…In this way one can estimate the ratio of fluorescence lifetimes from the energy transfer efficiency and the expected lifetime component once the fluorescence lifetime in the apo-protein is known. The average distance between Trp37 of different rubredoxins [21, and the iron is approximately 0.8 nm and between Tyr75 and the cluster edge of ferredoxins [22,26,27] is approximately 1.2 nm. The calculated transfer efficiency is then between 99% and 100% for rubredoxin and ferredoxin.…”

Section: Discussionmentioning

confidence: 99%

A comparative picosecond‐resolved fluorescence study of tryptophan residues in iron‐sulfur proteins

et al. 1994

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The fluorescence intensity and anisotropy decays of the intrinsic tryptophan emission from six Fe/S proteins (ranging from the very simplest ones to enzyme complexes containing one, two or more Trp residues) were measured. All proteins were examined in the reduced and the oxidized state. In either redox state each protein exhibits ultrarapid tryptophan fluorescence decay on the picosecond timescale contributing up to 93% of the total decay. Correlation times in the range of 1 ns or less were found for all six iron-sulfur proteins reflecting internal Trp motion. In addition, some proteins exhibit longer correlation times reflecting segmental motion and overall protein tumbling. The ultrarapid fluorescence decay in iron-sulfur proteins indicates efficient radiationless energy transfer between distant tryptophan residues and iron-sulfur clusters. Such an energy transfer mechanism can be accounted for by referring to the three-dimensional structures of rubredoxin and ferredoxin in calculating the transfer efficiency of the single tryptophan-iron-sulfur couple.

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Section: Discussionmentioning

confidence: 99%

A comparative picosecond‐resolved fluorescence study of tryptophan residues in iron‐sulfur proteins

et al. 1994

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“…This Fdx folding motif is among the most abundant in nature, and it has been well studied previously biochemically (18)(19)(20)(21)(22)(23), making Fdx an excellent candidate for quantitative, biophysical characterization. Moreover, the planttype Fdx folding motif has been found in numerous redox proteins and enzymes, as well as in functionally unrelated proteins that do not contain the [2Fe-2S] cluster, such as ubiquitin and the immunoglobulin-binding domain of protein G (24,25).…”

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confidence: 99%

“…The plant-type Fdx functions primarily as the electron acceptor of photosystem I, and upon reduction Fdx functions as an electron donor in a myriad of key metabolic pathways (e.g., NADP þ reduction, carbon assimilation, nitrite and sulfite reduction, glutamate synthesis, and thioredoxin reduction, etc.) (22,23,(31)(32)(33)(34)(35).…”

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confidence: 99%

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Allostery in the ferredoxin protein motif does not involve a conformational switch

Nechushtai

Lammert²,

Michaeli³

et al. 2011

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

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Regulation of protein function via cracking, or local unfolding and refolding of substructures, is becoming a widely recognized mechanism of functional control. Oftentimes, cracking events are localized to secondary and tertiary structure interactions between domains that control the optimal position for catalysis and/or the formation of protein complexes. Small changes in free energy associated with ligand binding, phosphorylation, etc., can tip the balance and provide a regulatory functional switch. However, understanding the factors controlling function in single-domain proteins is still a significant challenge to structural biologists. We investigated the functional landscape of a single-domain planttype ferredoxin protein and the effect of a distal loop on the electron-transfer center. We find the global stability and structure are minimally perturbed with mutation, whereas the functional properties are altered. Specifically, truncating the L1,2 loop does not lead to large-scale changes in the structure, determined via X-ray crystallography. Further, the overall thermal stability of the protein is only marginally perturbed by the mutation. However, even though the mutation is distal to the iron-sulfur cluster (∼20 Å), it leads to a significant change in the redox potential of the ironsulfur cluster (57 mV). Structure-based all-atom simulations indicate correlated dynamical changes between the surface-exposed loop and the iron-sulfur cluster-binding region. Our results suggest intrinsic communication channels within the ferredoxin fold, composed of many short-range interactions, lead to the propagation of long-range signals. Accordingly, protein interface interactions that involve L1,2 could potentially signal functional changes in distal regions, similar to what is observed in other allosteric systems.electron transfer | functional energy landscape | iron-sulfur proteins | protein folding O ver the last several decades, our understanding of protein function has evolved from a rather static perspective, where signaling and function have been understood through surface complementarity arguments, such as the "lock and key" paradigm (1, 2), to a more dynamic view where protein conformational fluctuations are inextricably linked to function (3). As our understanding of protein dynamics expands, we are revealing many mechanisms by which proteins exploit conformational fluctuations to perform cellular function. In multidomain proteins, relative repositioning of domains is often linked to their levels of activity. For example, large-scale domain rearrangements in the four-domain Src kinase (4) and C-terminal Src kinase (5, 6) lead to these proteins being in so-called "on" or "off" states, and functional regulation may be obtained by adjusting the balance between these conformations (7). In proteins such as adenylate kinase, domain rearrangements can be rate limiting during each round of catalysis (8), where the enzyme cycles between ligandcompetent and ligand-release conformations. Because the kinetics of these tra...

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“…The amino acid sequence identity between the various soluble ferredoxins is high (generally ca. 70%) for proteins ranging from cyanobacteria to higher plants [2,3]. At the molecular level, it is interesting to note that although soluble chloroplastic ferredoxin is small in size (93~100 amino acids), it is able to interact with a great variety of enzymes and to form strong protein-protein complexes [4,5].…”

Section: Introductionmentioning

confidence: 99%

Residue Glu‐91 of Chlamydomonas reinhardtii ferredoxin is essential for electron transfer to ferredoxin‐thioredoxin reductase

et al. 1997

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The (2Fe-2S) soluble ferredoxin from Chlamydomonas reinhardtii was mutated by site directed mutagenesis, using PCR and the expression plasmid pET-Fd as a template. The recombinant mutated proteins were purified to homogeneity and tested in the activation of NADP-malate dehydrogenase, a light dependent reaction in which ferredoxin thioredoxin reductase (FTR) and thioredoxin are involved. The mutation of residue Glu-91 (E92 in spinach, E94 in Anabaena) alone, either to GIn (E9IQ) or to Lys (E9IK), was found to completely abolish the reaction of the enzyme light activation. On the other hand, the mutants (E92Q) or (E92K) were as efficient as the wild type ferredoxin in this reaction whereas the double mutants (E91 Q/ E92Q) or (E9IKlE92K) had no activity. In addition, a triple mutant (D25AIE28QIE29Q) was also found to be inactive for this redox dependent light activation. All these mutations had much weaker effects on the ferredoxin/ferredoxin NADP reductase interaction as measured by the cytochrome c reduction assay. These results indicate that there is a recognition site for FTR in the C terminus part of ferredoxin, but also that a core of negatively charged residues in the al helix of ferredoxin might be important in the general process of light activation.

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Crystallization and structure determination of 2.5-.ANG. resolution of the oxidized iron-sulfur [2Fe-2S] ferredoxin isolated from Anabaena 7120

Cited by 190 publications

References 21 publications

A comparative picosecond‐resolved fluorescence study of tryptophan residues in iron‐sulfur proteins

A comparative picosecond‐resolved fluorescence study of tryptophan residues in iron‐sulfur proteins

Allostery in the ferredoxin protein motif does not involve a conformational switch

Residue Glu‐91 of Chlamydomonas reinhardtii ferredoxin is essential for electron transfer to ferredoxin‐thioredoxin reductase

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