scholarly journals The oxidation-state-dependent ATP-binding site of cytochrome c. Implication of an essential arginine residue and the effect of occupancy on the oxidation-reduction potential

1988 ◽  
Vol 252 (2) ◽  
pp. 349-355 ◽  
Author(s):  
B E Corthésy ◽  
C J Wallace
Keyword(s):  
Cytochrome C ◽  
Oxidation State ◽  
Dependent Manner ◽  
Redox Potentials ◽  
Redox Systems ◽  
Atp Binding Site ◽  
Oxidation Reduction ◽  
State Dependent ◽  
Oxidation Reduction Potential

Arg-91 is not part of the active site of cytochrome c that mediates binding and electron transfer, yet it is absolutely conserved in eukaryotic cytochromes c, indicating a special function. The physicochemical properties of analogues are unaffected by the modification of this residue, so they can be used with confidence to study the role of Arg-91. We have established limiting conditions under which this residue alone is specifically modified by cyclohexane-1,2-dione, and have subsequently shown that ATP, and to a lesser extent ADP or Pi, protects it from the action of the reagent in an oxidation-state-dependent manner. These observations strongly support the idea that this site exerts a controlling influence on cytochrome c activity in the electron transport or other cellular redox systems, and we have commenced a study of how that influence might operate. We find that the redox potentials of both cytochrome c and analogue are little affected by changing ATP or Pi concentrations.

scholarly journals The oxidation-state-dependent ATP-binding site of cytochrome c. A possible physiological significance

1986 ◽  
Vol 236 (2) ◽  
pp. 359-364 ◽  
Author(s):  
B E Corthésy ◽  
C J A Wallace
Keyword(s):  
Cytochrome C ◽  
Binding Site ◽  
Oxidation State ◽  
Biological Properties ◽  
Physiological Significance ◽  
Horse Heart Cytochrome ◽  
Atp Binding Site ◽  
Recognition Sites ◽  
State Dependent ◽  
Horse Heart Cytochrome C

Cytochrome c binds certain physiological anions that are known to modulate the biological properties of the protein, although it is not known whether this effect is fortuitous or has physiological significance. We have examined the ability of the protein and its semisynthetic analogues to associate with certain of these anions, e.g. ATP, ADP, Pi and citrate. Our results show that specific residues or clusters of residues on the surface of horse heart cytochrome c are involved in the recognition sites for these anions. We also observed that binding at one site is linked to the oxidation state of the protein.

scholarly journals On the relationship between oxidation-reduction potential and biological activity in cytochrome c analogues. Results from four novel two-fragment complexes

1987 ◽  
Vol 245 (3) ◽  
pp. 773-779 ◽  
Author(s):  
C J A Wallace ◽  
A E I Proudfoot
Keyword(s):  
Electron Transfer ◽  
Cytochrome C ◽  
Biological Activities ◽  
Amino Acid Residues ◽  
Redox Potentials ◽  
Peptide Bonds ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Stable Association ◽  
The Relationship

We have confirmed the propensity of fragments of cytochrome c to form complexes that reproduce the structure and, in part, the functionality, of the native protein by preparing four novel complexes. We have used trypsin under three different sets of conditions in sequence to prepare a contiguous two-fragment complex (1-55).(56-104). One of the intermediates is a stable overlapping complex (1-65).(56-104). Conditions for limited acid hydrolysis of peptide bonds in cytochrome c have been developed that optimize the yield of fragments (1-50) and (51-104). These two fragments also form a stable association, as do (1-50) and (56-104). These complexes are potentially useful for the semisynthesis of analogues modified in the region of the cleavage sites, which include a number of highly conserved amino acid residues, and are being used for studies of protein folding, interactions with oxidase, cytochrome c immunogenicity and of artificially induced spontaneous resyntheses between complexing fragments. Like other known two-fragment complexes of cytochrome c, they exhibit normal visible spectra, including the presence of the 695 nm band, indicative of a functional haem crevice. Studies of their biological activities and redox potentials lead to a number of conclusions on structure-function relationships in cytochrome c. Most significantly there is a linear relationship between the logarithm of electron-transfer rates from cytochrome c reductase and redox potential in this series of analogues, indicating that such transfer is thermodynamically controlled. This discovery contributes to our understanding of the interaction of cytochrome and reductase. Since the relationship is obeyed by other types of analogues, except for those that involve modification of the active site of cytochrome c, we have a useful diagnostic for those residues that participate directly in electron transfer.

scholarly journals Exploring Oxidation State Dependent Conformational Changes of Cytochrome C on Cardiolipin Containing Liposomes

2016 ◽  
Vol 110 (3) ◽  
pp. 422a ◽  
Author(s):  
Bridget Milorey ◽  
Lee Serpas ◽  
Leah Pandiscia ◽  
Reinhard Schweitzer-Stenner
Keyword(s):  
Cytochrome C ◽  
Oxidation State ◽  
Conformational Changes ◽  
State Dependent

Role of arginine-38 in regulation of the cytochrome c oxidation-reduction equilibrium

Biochemistry ◽  
1989 ◽  
Vol 28 (8) ◽  
pp. 3188-3197 ◽  
Author(s):  
Robert L. Cutler ◽  
Anne M. Davies ◽  
Steve Creighton ◽  
Arieh Warshel ◽  
Geoffrey R. Moore ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Oxidation Reduction
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