High-resolution refinement of yeast iso-1-cytochrome c and comparisons with other eukaryotic cytochromes c

Louie, G.V.; Brayer, G.D.

doi:10.1016/0022-2836(90)90197-t

Cited by 382 publications

(382 citation statements)

References 52 publications

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“…A similar cavity is observed in the iso-1-cytochrome c structure (Louie & Brayer, 1990). The structural and functional role of this cavity is unknown, but amino acid substitutions in the hydrophobic core of the protein have been shown to affect .…”

Section: Comparison Of the Structures Of Repa2mentioning

confidence: 53%

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The structure and function of omega loop A replacements in cytochrome c

et al. 1993

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The structural and functional consequences of replacing Q-loop A (residues 18-32) in yeast iso-1-cytochrome c with the corresponding loop of Rhodospirillum rubrum cytochrome c2 have been examined. The three-dimensional structure of this loop replacement mutant RepA2 cytochrome e, and a second mutant RepA2(Val20) cytochrome c in which residue 20 was back substituted to valine, were determined using X-ray diffraction techniques. A change in the molecular packing is evident in the RepA2 mutant protein, which has a phenylalanine at position 20, a residue considerably larger than the valine found in wild-type yeast iso-I-cytochrome e. The side chain of Phe 20 is redirected toward the molecular surface, altering the packing of this region of 0-loop A with the hydrophobic core of the protein. In the RepA2(Val20) structure, Q-loop A contains a valine at position 20, which restores the original wild-type packing arrangement of the hydrophobic core. Also, as a result of Q-loop A replacement, residue 26 is changed from a histidine to asparagine, which results in displacements of the main-chain atoms near residue 44 to which residue 26 is hydrogen bonded. In vivo studies of the growth rate of the mutant strains on nonfermentable media indicate that the RepA2(Val20) cytochrome c behaves much like the wild-type yeast iso-1 protein, whereas the stability and function of the RepA2 cytochrome c showed a temperature dependence. The midpoint reduction potential measured by cyclic voltammetry of the RepA2 mutant is 271 mV at 25 "C. This is 19 mV less than the wildtype and RepA2(Val20) proteins (290 mV) and may result from disruption of the hydrophobic packing in the heme pocket and increased mobility of Q-loop A in RepA2 cytochrome c. The temperature dependence of the reduction potential is also greatly enhanced in the RepA2 protein.

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Section: Comparison Of the Structures Of Repa2mentioning

confidence: 53%

“…A starting model of RepAZ(Val20) cytochrome c was constructed from the coordinates of wild-type yeast iso-lcytochrome c (Louie & Brayer, 1990). At each position of differing amino acid sequence, the residue present was initially modeled as an alanine (Fig.…”

Section: Percentage Of Reflections Withmentioning

confidence: 99%

The structure and function of omega loop A replacements in cytochrome c

et al. 1993

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“…Thus, the cyt c-CL interaction plays an important role in cells since it modulates the protein behavior determining whether cyt c should perform its 'normal' role in the respiratory chain or, conversely, is to be released into the cytosol where it participates in the apoptotic event (see [40] and references therein). Unlike the equine protein, cyt c from yeast does not participate in cell apoptosis [16,17].…”

Section: Discussionmentioning

confidence: 99%

“…The two proteins have a similar tertiary architecture [14][15][16][17], but yeast cyt c displays a significantly lower stability than the protein from horse, it does not bind ATP and, contrary to horse cyt c, lacks pro-apoptotic activity [18,19]. The CL-cyt c binding reaction has been investigated in the absence and in the presence of ATP and sodium chloride, two compounds that significantly influence the (horse cyt c)-CL binding process [5].…”

Section: Introductionmentioning

confidence: 99%

The effects of ATP and sodium chloride on the cytochrome c–cardiolipin interaction: The contrasting behavior of the horse heart and yeast proteins

Sinibaldi¹,

Droghetti²,

Polticelli³

et al. 2011

Journal of Inorganic Biochemistry

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In cells a portion of cytochrome c (cyt c) (15-20%) is tightly bound to cardiolipin (CL), one of the phospholipids constituting the mitochondrial membrane. The CL-bound protein, which has nonnative tertiary structure, altered heme pocket, and disrupted Fe(III)-M80 axial bond, is thought to play a role in the apoptotic process. This has attracted considerable interest in order to clarify the mechanisms governing the cyt c-CL interaction. Herein we have investigated the binding reaction of CL with the c-type cytochromes from horse heart and yeast. Although the two proteins possess a similar tertiary architecture, yeast cyt c displays lower stability and, contrary to the equine protein, it does not bind ATP and lacks pro-apoptotic activity. The study has been performed in the absence and in the presence of ATP and NaCl, two compounds that influence the (horse cyt c)-CL binding process and, thus, the pro-apoptotic activity of the protein. The two proteins behave differently: while CL interaction with horse cyt c is strongly influenced by the two effectors, no effect is observed for yeast cyt c. It is noteworthy that NaCl induces dissociation of the (horse cyt c)-CL complex but has no influence on that of yeast cyt c. The differences found for the two proteins highlight that specific structural factors, such as the different local structure conformation of the regions involved in the interactions with either CL or ATP, can significantly affect the behavior of cyt c in its reaction with liposomes and the subsequent pro-apoptotic action of the protein.

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“…2 Recipient of an EMBO long term fellowship. Present address: Institut de Biologie Physico-Chimique, UMR7141 CNRS/University Paris VI, 13 Rue Pierre et Marie Curie, 75005 Paris, France. 3 To whom correspondence should be addressed.…”

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confidence: 99%

Ligand Dynamics in an Electron Transfer Protein

Silkstone

Jasaitis

Wilson

et al. 2007

Journal of Biological Chemistry

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Substitution of the heme coordination residue Met-80 of the electron transport protein yeast iso-1-cytochrome c allows external ligands like CO to bind and thus increase the effective redox potential. This mutation, in principle, turns the protein into a quasi-native photoactivable electron donor. We have studied the kinetic and spectral characteristics of geminate recombination of heme and CO in a series of single M80X (X ‫؍‬ Ala, Ser, Asp, Arg) mutants, using femtosecond transient absorption spectroscopy. In these proteins, all geminate recombination occurs on the picosecond and early nanosecond time scale, in a multiphasic manner, in which heme relaxation takes place on the same time scale. The extent of geminate recombination varies from >99% (Ala, Ser) to ϳ70% (Arg), the latter value being in principle low enough for electron injection studies. The rates and extent of the CO geminate recombination phases are much higher than in functional ligand-binding proteins like myoglobin, presumably reflecting the rigid and hydrophobic properties of the heme environment, which are optimized for electron transfer. Thus, the dynamics of CO recombination in cytochrome c are a tool for studying the heme pocket, in a similar way as NO in myoglobin. We discuss the differences in the CO kinetics between the mutants in terms of the properties of the heme environment and strategies to enhance the CO escape yield. Experiments on double mutants in which Phe-82 is replaced by Asp or Gly as well as the M80D substitution indicate that such steric changes substantially increase the motional freedom-dissociated CO.

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High-resolution refinement of yeast iso-1-cytochrome c and comparisons with other eukaryotic cytochromes c

Cited by 382 publications

References 52 publications

The structure and function of omega loop A replacements in cytochrome c

The structure and function of omega loop A replacements in cytochrome c

The effects of ATP and sodium chloride on the cytochrome c–cardiolipin interaction: The contrasting behavior of the horse heart and yeast proteins

Ligand Dynamics in an Electron Transfer Protein

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