The finding that cytochrome c (cyt c) plays a role in programmed cell death after its release from the mitochondrion has recently renewed interest in this protein. The structural changes in cytochrome c observed at early stages of the apoptotic process have been related to changes occurring in the protein when it forms a complex with phospholipid vesicles; Among the lipids constituting the membrane, cardiolipin is the one thought to bind to cyt c. In this paper, we have investigated the influence exerted by ionic strength on cytochrome c-cardiolipin interaction and found that formation of the cytochrome c-cardiolipin complex occurs via two distinct transitions, implying a high-affinity site and a low-affinity site. Ionic strength significantly influences complex stability; sodium chloride dissociates the complex through two distinct transitions, the second of which occurs at a very high anion concentration. ATP also dissociates the complex, but under the conditions that were investigated, its action is limited to the high-affinity site. The dissociation process is characterized by a very slow kinetic rate constant (k(obs) = 4.2 x 10(-3) s(-1)) and requires several minutes to be completed. We ascribe it to the high activation barrier met by the protein when restoring the native Fe(III)-M80 axial bond. The peroxidase activity shown by cardiolipin-bound cytochrome c is indicative of a less packed protein tertiary conformation in the complex. In line with earlier reports, these data highlight the manifold functions of cytochrome c besides the well-known role it plays in oxidative phosphorylation, shedding more light on the properties of the cytochrome c-cardiolipin complex, involved in the progression of early stages of apoptosis.

Sinibaldi, F., Fiorucci, L., Patriarca, A., Lauceri, R., Ferri, T., Coletta, M., et al. (2008). Insights into cytochrome c-cardiolipin interaction. Role played by ionic strength. BIOCHEMISTRY, 47(26), 6928-6935 [10.1021/bi800048v].

Insights into cytochrome c-cardiolipin interaction. Role played by ionic strength

FIORUCCI, LAURA;COLETTA, MASSIMILIANO;SANTUCCI, ROBERTO
2008

Abstract

The finding that cytochrome c (cyt c) plays a role in programmed cell death after its release from the mitochondrion has recently renewed interest in this protein. The structural changes in cytochrome c observed at early stages of the apoptotic process have been related to changes occurring in the protein when it forms a complex with phospholipid vesicles; Among the lipids constituting the membrane, cardiolipin is the one thought to bind to cyt c. In this paper, we have investigated the influence exerted by ionic strength on cytochrome c-cardiolipin interaction and found that formation of the cytochrome c-cardiolipin complex occurs via two distinct transitions, implying a high-affinity site and a low-affinity site. Ionic strength significantly influences complex stability; sodium chloride dissociates the complex through two distinct transitions, the second of which occurs at a very high anion concentration. ATP also dissociates the complex, but under the conditions that were investigated, its action is limited to the high-affinity site. The dissociation process is characterized by a very slow kinetic rate constant (k(obs) = 4.2 x 10(-3) s(-1)) and requires several minutes to be completed. We ascribe it to the high activation barrier met by the protein when restoring the native Fe(III)-M80 axial bond. The peroxidase activity shown by cardiolipin-bound cytochrome c is indicative of a less packed protein tertiary conformation in the complex. In line with earlier reports, these data highlight the manifold functions of cytochrome c besides the well-known role it plays in oxidative phosphorylation, shedding more light on the properties of the cytochrome c-cardiolipin complex, involved in the progression of early stages of apoptosis.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/10
English
Alkali metals; Antigens; Cell death; Cell membranes; Dissociation; Flow interactions; Lipids; Liposomes; Phospholipids; Rate constants; Sodium; Sodium chloride; Theorem proving; (I ,J) conditions; anion concentrations; apoptotic processes; Cardiolipin (CL); Complex stability; Cytochrome c (Cyt c); Dissociation processes; Early stages; Kinetic rates; phospholipid vesicles; Programmed cell death (PCD); Strength (IGC: D5/D6); Structural changes; Ionic strength; adenosine triphosphate; cardiolipin; cytochrome c; ferric ion; peroxidase; sodium chloride; animal tissue; apoptosis; article; binding affinity; binding site; enzyme kinetics; ionic strength; nonhuman; oxidative phosphorylation; priority journal; protein conformation; protein function; protein interaction; Adenosine Triphosphate; Animals; Cardiolipins; Cattle; Circular Dichroism; Cytochromes c; Horses; Kinetics; Osmolar Concentration; Peroxidase; Protein Binding; Titrimetry; Kobus
Sinibaldi, F., Fiorucci, L., Patriarca, A., Lauceri, R., Ferri, T., Coletta, M., et al. (2008). Insights into cytochrome c-cardiolipin interaction. Role played by ionic strength. BIOCHEMISTRY, 47(26), 6928-6935 [10.1021/bi800048v].
Sinibaldi, F; Fiorucci, L; Patriarca, A; Lauceri, R; Ferri, T; Coletta, M; Santucci, R
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2108/41191
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