Protein dynamics and function: Making new strides with an old warhorse, the alkaline conformational transition of cytochrome c

Cherney, Melisa M.; Bowler, Bruce E.

doi:10.1016/j.ccr.2010.09.014

Cited by 50 publications

(129 citation statements)

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“…We hypothesize that kinetics of the ferric thiolate formation depends on protein rearrangements. Previous studies of yeast cyt c have illustrated that, as the stability of the protein decreases, the rates of the protein rearrangements involving heme ligands and surrounding residues within the pocket increase (34). The decrease in the folding stability of our variants with decrease in pH parallels the pH-dependent increase in the rate constant k 3, SH-S − (Fig.…”

Section: Resultsmentioning

confidence: 60%

“…However, our attempts to recombinantly make yeast Met80Cys variants have yielded proteins with an oxidized Cys80 side chain, which did not ligate as a thiolate to the heme upon oxidation. The properties of the yeast and horse heart proteins are very similar, but the former protein is less stable (34,51), with the Met80 loop that is more mobile and unfolds more easily (Fig. S2).…”

Section: Discussionmentioning

confidence: 88%

“…Under alkaline conditions, cyt c undergoes a conformational transition where Lys residues 72, 73, and 79 substitute the native Met80 ligand at the heme (22,33,34). The pK a of this transition in native and mutated cyt c proteins reflects the ligand's propensity for heme coordination.…”

Section: Resultsmentioning

confidence: 99%

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Redox-dependent stability, protonation, and reactivity of cysteine-bound heme proteins

Zhong

Lisi

Collins

et al. 2014

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

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Cysteine-bound hemes are key components of many enzymes and biological sensors. Protonation (deprotonation) of the Cys ligand often accompanies redox transformations of these centers. To characterize these phenomena, we have engineered a series of Thr78Cys/Lys79Gly/Met80X mutants of yeast cytochrome c (cyt c) in which Cys78 becomes one of the axial ligands to the heme. At neutral pH, the protonation state of the coordinated Cys differs for the ferric and ferrous heme species, with Cys binding as a thiolate and a thiol, respectively. Analysis of redox-dependent stability and alkaline transitions of these model proteins, as well as comparisons to Cys binding studies with the minimalist heme peptide microperoxidase-8, demonstrate that the protein scaffold and solvent interactions play important roles in stabilizing a particular Cys-heme coordination. The increased stability of ferric thiolate compared with ferrous thiol arises mainly from entropic factors. This robust cyt c model system provides access to all four forms of Cys-bound heme, including the ferric thiol. Protein motions control the rates of heme redox reactions, and these effects are amplified at low pH, where the proteins are less stable. Thermodynamic signatures and redox reactivity of the model Cys-bound hemes highlight the critical role of the protein scaffold and its dynamics in modulating redox-linked transitions between thiols and thiolates.metalloenzyme | folding | electron transfer

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Section: Resultsmentioning

confidence: 60%

Section: Discussionmentioning

confidence: 88%

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Redox-dependent stability, protonation, and reactivity of cysteine-bound heme proteins

Zhong

Lisi

Collins

et al. 2014

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

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“…The data clearly reveal two different phases which merge into a single one at high phosphate ion concentration. Cherney and Bowler assigned the state to the deprotonation of one of the propionic acid substituents of the heme group, which is known to exhibit a very high pK-value [114]. A similar state called III 3.5 was observed from site specific IR-experiments of Weinkam et al, which as III * is populated at pH 9 [115].…”

Section: Folding and Unfolding Ofmentioning

confidence: 64%

“…Our analysis showed that both III ⇔ III * and III * ⇔ IV equilibria are describable by a Hill-type equation, which indicates the involvement of more than a single proton. As indicated above, Cherney and Bowler suggested that one of the propionic acid groups of the heme is a candidate [114].…”

Section: Folding and Unfolding Ofmentioning

confidence: 99%

Cytochrome c: A Multifunctional Protein Combining Conformational Rigidity with Flexibility

Schweitzer‐Stenner

2014

New Journal of Science

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Cytochrome has served as a model system for studying redox reactions, protein folding, and more recently peroxidase activity induced by partial unfolding on membranes. This review illuminates some important aspects of the research on this biomolecule. The first part summarizes the results of structural analyses of its active site. Owing to heme-protein interactions the heme group is subject to both in-plane and out-of-plane deformations. The unfolding of the protein as discussed in detail in the second part of this review can be induced by changes of pH and temperature and most prominently by the addition of denaturing agents. Both the kinetic and thermodynamic folding and unfolding involve intermediate states with regard to all unfolding conditions. If allowed to sit at alkaline pH (11.5) for a week, the protein does not return to its folding state when the solvent is switched back to neutral pH. It rather adopts a misfolded state that is prone to aggregation via domain swapping. On the surface of cardiolipin containing liposomes, the protein can adopt a variety of partially unfolded states. Apparently, ferricytochrome c can perform biological functions even if it is only partially folded.

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Redox‐State‐Mediated Regulation of Cytochrome c Release in Apoptosis Revealed by Surface‐Enhanced Raman Scattering on Nickel Substrates

Zhu¹,

Jiang²,

Ma³

et al. 2019

Angewandte Chemie

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Protein dynamics and function: Making new strides with an old warhorse, the alkaline conformational transition of cytochrome c

Cited by 50 publications

References 115 publications

Redox-dependent stability, protonation, and reactivity of cysteine-bound heme proteins

Redox-dependent stability, protonation, and reactivity of cysteine-bound heme proteins

Cytochrome c: A Multifunctional Protein Combining Conformational Rigidity with Flexibility

Redox‐State‐Mediated Regulation of Cytochrome c Release in Apoptosis Revealed by Surface‐Enhanced Raman Scattering on Nickel Substrates

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