The interaction between cytochrome c (Cyt c) and cardiolipin (CL) plays a vital role in the early stages of apoptosis. The binding of CL to Cyt c induces a considerable increase in its peroxidase activity that has been attributed to the partial unfolding of the protein, dissociation of the Met80 axial ligand, and formation of non-native conformers. Although the interaction between Cyt c and CL has been extensively studied, there is still no consensus regarding the conformational rearrangements of Cyt c that follow the protein-lipid interaction. To rationalize the different results and gain better insight into the Cyt c-CL interaction, we have studied the formation of the CL complex of the horse heart wild-type protein and selected mutants in which residues considered to play a key role in the interaction with CL (His26, His33, Lys72, Lys73, and Lys79) have been mutated. The analysis was conducted at both room temperature and low temperatures via ultraviolet-visible absorption, resonance Raman, and electron paramagnetic resonance spectroscopies. The trigger and the sequence of CL-induced structural variations are discussed in terms of disruption of the His26-Pro44 hydrogen bond. We unequivocally identify the sixth ligand in the partially unfolded, non-native low-spin state that Cyt c can adopt following the protein-lipid interaction, as a His ligation, ruling out the previously proposed involvement of a Lys residue or an OH- ion.

Milazzo, L., Tognaccini, L., Howes, B.D., Sinibaldi, F., Piro, M.C., Fittipaldi, M., et al. (2017). Unravelling the non-native low-spin state of the cytochrome c-cardiolipin complex: evidence of the formation of a His-ligated species only. BIOCHEMISTRY, 56(13), 1887-1898 [10.1021/acs.biochem.6b01281].

Unravelling the non-native low-spin state of the cytochrome c-cardiolipin complex: evidence of the formation of a His-ligated species only

BARATTO, MARIA CAMILLA;POGNI, REBECCA;
2017-01-01

Abstract

The interaction between cytochrome c (Cyt c) and cardiolipin (CL) plays a vital role in the early stages of apoptosis. The binding of CL to Cyt c induces a considerable increase in its peroxidase activity that has been attributed to the partial unfolding of the protein, dissociation of the Met80 axial ligand, and formation of non-native conformers. Although the interaction between Cyt c and CL has been extensively studied, there is still no consensus regarding the conformational rearrangements of Cyt c that follow the protein-lipid interaction. To rationalize the different results and gain better insight into the Cyt c-CL interaction, we have studied the formation of the CL complex of the horse heart wild-type protein and selected mutants in which residues considered to play a key role in the interaction with CL (His26, His33, Lys72, Lys73, and Lys79) have been mutated. The analysis was conducted at both room temperature and low temperatures via ultraviolet-visible absorption, resonance Raman, and electron paramagnetic resonance spectroscopies. The trigger and the sequence of CL-induced structural variations are discussed in terms of disruption of the His26-Pro44 hydrogen bond. We unequivocally identify the sixth ligand in the partially unfolded, non-native low-spin state that Cyt c can adopt following the protein-lipid interaction, as a His ligation, ruling out the previously proposed involvement of a Lys residue or an OH- ion.
2017
Milazzo, L., Tognaccini, L., Howes, B.D., Sinibaldi, F., Piro, M.C., Fittipaldi, M., et al. (2017). Unravelling the non-native low-spin state of the cytochrome c-cardiolipin complex: evidence of the formation of a His-ligated species only. BIOCHEMISTRY, 56(13), 1887-1898 [10.1021/acs.biochem.6b01281].
File in questo prodotto:
File Dimensione Formato  
Biochemistry_2017.pdf

non disponibili

Descrizione: Biochemistry_2017
Tipologia: PDF editoriale
Licenza: NON PUBBLICO - Accesso privato/ristretto
Dimensione 2.26 MB
Formato Adobe PDF
2.26 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
BARATTO-Unravelling the non native-Post-Print.pdf

accesso aperto

Descrizione: Accepted Manuscript
Tipologia: Post-print
Licenza: PUBBLICO - Pubblico con Copyright
Dimensione 1.74 MB
Formato Adobe PDF
1.74 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/1006589