The reaction of cytochrome c with [Fe(EDTA)(H2O)]−

Williams, G. D.; Eley, Crispin G. S.; Moore, Geoffrey R.; Robinson, Martin N.; Williams, R. J. P.

doi:10.1016/0014-5793(82)80754-0

Cited by 17 publications

(6 citation statements)

References 21 publications

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“…The LiBr-induced X state is in low spin state and has absorption band at 695 nm as that of the native state of cyt- c . The extinction coefficient values at 620 nm and 695 nm for the native and acid-induced MG states of cyt- c ( Table 2 ) are in excellent agreement with those of other homolog of cyt- c reported earlier [ 12 , 52 ]. As shown in Table 2 , the spectral intensity at 695 nm follows the trend native state > X-state in LiBr ~ 0.5 M NaCl-induced MG state at acidic pH > X-state in LiCl > X-state in LiClO 4 .…”

Section: Resultssupporting

confidence: 90%

Heterogeneity of Equilibrium Molten Globule State of Cytochrome c Induced by Weak Salt Denaturants under Physiological Condition

et al. 2015

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While many proteins are recognized to undergo folding via intermediate(s), the heterogeneity of equilibrium folding intermediate(s) along the folding pathway is less understood. In our present study, FTIR spectroscopy, far- and near-UV circular dichroism (CD), ANS and tryptophan fluorescence, near IR absorbance spectroscopy and dynamic light scattering (DLS) were used to study the structural and thermodynamic characteristics of the native (N), denatured (D) and intermediate state (X) of goat cytochorme c (cyt-c) induced by weak salt denaturants (LiBr, LiCl and LiClO4) at pH 6.0 and 25°C. The LiBr-induced denaturation of cyt-c measured by Soret absorption (Δε 400) and CD ([θ]409), is a three-step process, N ↔ X ↔ D. It is observed that the X state obtained along the denaturation pathway of cyt-c possesses common structural and thermodynamic characteristics of the molten globule (MG) state. The MG state of cyt-c induced by LiBr is compared for its structural and thermodynamic parameters with those found in other solvent conditions such as LiCl, LiClO4 and acidic pH. Our observations suggest: (1) that the LiBr-induced MG state of cyt-c retains the native Met80-Fe(III) axial bond and Trp59-propionate interactions; (2) that LiBr-induced MG state of cyt-c is more compact retaining the hydrophobic interactions in comparison to the MG states induced by LiCl, LiClO4 and 0.5 M NaCl at pH 2.0; and (3) that there exists heterogeneity of equilibrium intermediates along the unfolding pathway of cyt-c as highly ordered (X1), classical (X2) and disordered (X3), i.e., D ↔ X3 ↔ X2 ↔ X1 ↔ N.

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Section: Resultssupporting

confidence: 90%

Heterogeneity of Equilibrium Molten Globule State of Cytochrome c Induced by Weak Salt Denaturants under Physiological Condition

et al. 2015

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“…Since our initial studies of the binding of [Cr(CN),I3-and [Fe(edta)(H20)] -to cytochrome c [6,16,17] the aliphatic amino acid assignments have been almost completed [18,20,211, thus allowing a much better definition of their binding sites (see Discussion). Further resonance assignments and corrections to four previously reported sets of assignments are given in the present paper.…”

Section: Ion Binding To Cytochrome Cmentioning

confidence: 99%

“…3 of [16] and Fig. 2 of [17]). Thus the protein can distinguish between three reagents carrying negative charge.…”

Section: Cation-binding Sites On Cytochrome Cmentioning

confidence: 99%

Ion binding to cytochrome c

Areán¹,

Moore²,

Williams³

et al. 1988

European Journal of Biochemistry

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This paper is a further study of ion binding to protein surfaces and builds on the studies of the binding of [Cr(CN), . In the present paper the binding of polyaminocarboxylate complexes of gadolinium have been studied, Eight ion-binding sites have been identified on the surface of cytochrome c. These exhibit different binding specificities which, in some cases, are not fully understood. However it is clear that simple outer-sphere interactions are not the sole determining factor for the association of metal ion complexes with proteins. The NMR paramagnetic difference spectrum method has been shown to be good at locating binding sites and revealing qualitative differences in their relative affinities for a range of complex types. However the use of relaxation probes is not a good method for the quantitative determination of binding constants; for this, isostructural shift probes must be sought.

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“…NMR investigations on the complex formation between proteins and Cr III compounds have been made,33, 34 and both the hydrophobic and negative patches were shown to be the [Cr(NH 3 ) 6 ] 3+ interacting sites for PC,34 whereas several [Cr(NH 3 ) 6 ] 3+ binding sites were detected for cyt c 33. Williams and coworkers identified eight ion‐binding sites on the surface of cyt c by the NMR paramagnetic difference spectrum method 35–37…”

Section: Interaction Of Electron Transfer Proteins With Inorganic Commentioning

confidence: 99%

“…Least‐squares fitting of k obs was successful only for n ≥ 6, supporting that cyt c has many sites for [Fe(CN) 6 ] 4– interaction. Actually, cyt c recognizes its redox partner protein through more than two of its positively charged sites, and four anion binding sites have been identified by NMR spectroscopy 35–37 . k ′ was calculated to be 128 ± 5 s –1 when n = 6, and the K values for various Asp peptides obtained for n = 6 are listed in Table 3.…”

Section: Effect Of Charged Peptides On Electron Transfer Proteinsmentioning

confidence: 99%

Weak interactions and molecular recognition in systems involving electron transfer proteins

Hirota

Yamauchi

2001

The Chemical Record

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Electrostatic interactions and other weak interactions between amino acid side chains on protein surfaces play important roles in molecular recognition, and the mechanism of their intermolecular interactions has gained much interest. We established that charged peptides are useful for investigating the molecular recognition character of proteins and their molecular interaction induced structural changes. Positively charged lysine peptides competitively inhibited electron transfer from reduced cytochrome f (cyt f or cytochrome c (cyt c) to oxidized plastocyanin (PC), due to neutralization of the negatively charged site of PC by formation of PC-lysine peptide complexes. Lysine peptides also inhibited electron transfer from cyt c to cytochrome c peroxidase. Likewise, negatively charged aspartic acid peptides interacted with the positively charged sites of cytfand cyt c, and competitively inhibited electron transfer from reduced cytfor cyt c to oxidized PC and from [Fe(CN)6]4- to oxidized cyt c. Changes in the geometry and a shift to a higher redox potential of the active site Cu of PC on oligolysine binding were detected by spectroscopic and electrochemical measurements, owing to the absence of absorption in the visible region for lysine peptides. Structural and redox potential changes were also observed for cyt f and cyt c by interaction with aspartic acid peptides.

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The reaction of cytochrome c with [Fe(EDTA)(H₂O)]⁻

Abstract: The relevance of this finding to the electron‐transfer function of cytochrome c is discussed.

Cited by 17 publications

References 21 publications

Heterogeneity of Equilibrium Molten Globule State of Cytochrome c Induced by Weak Salt Denaturants under Physiological Condition

Heterogeneity of Equilibrium Molten Globule State of Cytochrome c Induced by Weak Salt Denaturants under Physiological Condition

Ion binding to cytochrome c

Weak interactions and molecular recognition in systems involving electron transfer proteins

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