Unravelling the Non-Native Low-Spin State of the Cytochrome c-Cardiolipin Complex: Evidence of the Formation of a His-Ligated Species Only
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 axi...
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| Vydané v: | Biochemistry (Easton) Ročník 56; číslo 13; s. 1887 |
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| Hlavní autori: | , , , , , , , , , |
| Médium: | Journal Article |
| Jazyk: | English |
| Vydavateľské údaje: |
United States
04.04.2017
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| Predmet: | |
| ISSN: | 1520-4995, 1520-4995 |
| On-line prístup: | Zistit podrobnosti o prístupe |
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| Shrnutí: | 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. |
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| Bibliografia: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 1520-4995 1520-4995 |
| DOI: | 10.1021/acs.biochem.6b01281 |