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.
|Tipologia:||Articolo su rivista|
|Citazione:||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.|
|Settore Scientifico Disciplinare:||Settore BIO/10|
|Revisione (peer review):||Sì, ma tipo non specificato|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1021/bi800048v|
|Stato di pubblicazione:||Pubblicato|
|Data di pubblicazione:||2008|
|Titolo:||Insights into cytochrome c-cardiolipin interaction. Role played by ionic strength|
|Autori:||Sinibaldi, F; Fiorucci, L; Patriarca, A; Lauceri, R; Ferri, T; Coletta, M; Santucci, R|
|Appare nelle tipologie:||01 - Articolo su rivista|