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

Sinibaldi F.;Piro M. C.;Santucci R.;
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
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore BIO/10 - BIOCHIMICA
English
Con Impact Factor ISI
Animals; Carbon Monoxide; Cardiolipins; Cloning, Molecular; Cytochromes c; Escherichia coli; Gene Expression; Genes, Synthetic; Histidine; Horses; Hydrogen Bonding; Methionine; Myocardium; Protein Binding; Protein Folding; Protein Structure, Secondary; Protein Unfolding; Recombinant Proteins; Temperature
https://pubs.acs.org/doi/10.1021/acs.biochem.6b01281
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].
Milazzo, L; Tognaccini, L; Howes, Bd; Sinibaldi, F; Piro, Mc; Fittipaldi, M; Baratto, Mc; Pogni, R; Santucci, R; Smulevich, G
Articolo su rivista
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/199408
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