Definition of a Nucleotide Binding Site on Cytochrome c by Photoaffinity Labeling

McIntosh, David B.; Parrish, Jonathan C.; Wallace, Carmichael J. A.

doi:10.1074/jbc.271.31.18379

Cited by 24 publications

(26 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Likewise, the effect of ATP on the fluorescence quenching by the modified protein was significantly smaller. Yet, the fact that even for the Arg 91 3 Nle mutant a slightly enhanced quenching was seen suggests that the deletion of the guanidino group leaves intact the contribution of the other components of the binding site (48) and that the loss of ATP binding to the mutated site is not complete (Fig. 4, panel A), confirming the affinity column data (Table II).…”

Section: Atp-induced Changes In the Fluorescence Of [Zn 2ϩsupporting

confidence: 76%

ATP Induces a Conformational Change in Lipid-bound Cytochrome c

Tuominen

Zhu

Wallace

et al. 2001

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Section: Atp-induced Changes In the Fluorescence Of [Zn 2ϩsupporting

confidence: 76%

ATP Induces a Conformational Change in Lipid-bound Cytochrome c

Tuominen

Zhu

Wallace

et al. 2001

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

“…Tyr-97 is located on the conventional "right side" of the molecule (12), and the side chain is essentially solventexposed and thus accessible for a kinase and a phosphatase. Tyr-97 is part of the only true R helical stretch in Cyt c, encompassing residues 91-101 (3), and two neighbors of Tyr-97, Leu-94 and Leu-98, are spatially packed against the heme group (25).…”

Section: Isolation Of In Vivo Phosphorylated Cyt Cmentioning

confidence: 99%

New Prospects for an Old Enzyme: Mammalian Cytochrome c Is Tyrosine-Phosphorylated in Vivo

Lee

Salomon

et al. 2006

Biochemistry

View full text Add to dashboard Cite

Mammalian cytochrome c (Cyt c) has two primary functions: transfer of electrons from the bc 1 complex to cytochrome c oxidase (COX) as part of the mitochondrial electron transport chain (ETC), and participation in type II apoptosis. Several studies have indicated that components of the ETC can be phosphorylated, and we have recently shown that the Cyt c electron acceptor COX is phosphorylated on Tyr-304 of subunit I in liver upon activation of the cAMP-dependent pathway, leading to strong enzyme inhibition. However, covalent modification of Cyt c through phosphorylation has not yet been reported. We have isolated Cyt c from cow heart under conditions that preserve the physiological in vivo phosphorylation status. Western analysis with an anti-phosphotyrosine antibody indicated tyrosine phosphorylation. The site of phosphorylation was definitively assigned by immobilized metal affinity chromatography/nano-liquid chromatography/electrospray ionization mass spectrometry (IMAC/nano-LC/ ESI-MS) to Tyr-97, one of the four tyrosine residues present in Cyt c. The phosphorylated tyrosine is part of a motif that contains five residues identical to the tyrosine phosphorylation site in COX subunit I. Spectral analysis revealed that the characteristic 695 nm absorption band is shifted to 687 nm and reversed after treatment with alkaline phosphatase. This band results from the Met-80-heme iron bond, and its shift might indicate changes in the catalytic heme crevice. In vivo phosphorylated Cyt c shows enhanced sigmoidal kinetics with COX, and half-maximal turnover is observed at a Cyt c substrate concentration of 5.5 µM compared to 2.5 µM for alkaline phosphatase-treated Cyt c. Possible consequences of Tyr-97 phosphorylation with respect to cardiolipin binding and of location of Tyr-97 in close proximity to Lys-7, a crucial residue for interaction with Apaf-1 during apoptosis, are discussed.

show abstract

“…The most disruptive of these were the iron hexacyanides and the polyphosphate anions ATP\dATP. It has been shown that anions directly bind cytochrome c around the polylysine binding pocket [13,14]. This binding of ATP may be physiologically important for feedback inhibition of the respiratory chain [15].…”

mentioning

confidence: 99%

Importance of the redox state of cytochrome c during caspase activation in cytosolic extracts

Hampton

Zhivotovsky

Slater

et al. 1998

Biochemical Journal

118

View full text Add to dashboard Cite

The export of cytochrome c from mitochondria to the cytoplasm has been detected during apoptosis. Addition of cytochrome c to cytosolic extracts can activate the caspases, suggesting that this export could be an important intracellular signal for initiating the apoptotic programme. We have investigated the mechanism of caspase activation by cytochrome c. Mitochondrial cytochrome c normally shuttles electrons between complexes III and IV of the electron transport chain. Interaction with these complexes is dependent on electrostatic interactions via a polylysine binding pocket. Cytosolic caspase activation was only observed with intact holocytochrome c, and increasing the ionic composition of the extracts prevented activation, suggesting that stringent allosteric interactions between cytochrome c and other cytoplasmic factors are necessary. Cytochrome c was fully reduced within 5 min of addition to the cytosolic extracts. Potassium ferricyanide could maintain cytochrome c in an oxidized state, but care was taken to use ferricyanide at concentrations where its polyanion effect did not cause interference. The oxidized form of cytochrome c was able to activate the caspases. We conclude that reduced cytochrome c will function in the cytoplasm; however, its reduction is not a critical step, and electron transfer from cytochrome c to its cytoplasmic-binding partner(s) is not necessary in the pathway leading to apoptosis.

show abstract

Definition of a Nucleotide Binding Site on Cytochrome c by Photoaffinity Labeling

Cited by 24 publications

References 40 publications

ATP Induces a Conformational Change in Lipid-bound Cytochrome c

ATP Induces a Conformational Change in Lipid-bound Cytochrome c

New Prospects for an Old Enzyme: Mammalian Cytochrome c Is Tyrosine-Phosphorylated in Vivo

Importance of the redox state of cytochrome c during caspase activation in cytosolic extracts

Contact Info

Product

Resources

About