Covalent binding and anchoring of cytochrome c to mitochondrial mimetic membranes promoted by cholesterol carboxyaldehyde.
Mitochondrial cholesterol has been reported to be increased under specific pathological conditions associated with enhanced oxidative stress parameters. In this scenario, cholesterol oxidation would be increased, leading to the production of reactive aldehydes, including cholesterol carboxyaldehyde (ChAld). By using SDS micelles as a mitochondrial mimetic model, we have demonstrated that ChAld covalently modifies cytochrome c (cytc), a protein known to participate in electron transport and apoptosis signaling. This mimetic model induces changes in cytc structure in the same way as mitochondrial membranes do. Tryptic digestion of the cytc-ChAld adduct followed by MALDI-TOF/TOF analyses revealed that modifications occur at Lys residues (K22) localized at cytc site L, a site involved in protein-protein and protein-membrane interactions. Interestingly, ChAld ligation prevented cytc detachment from liposomes even under high ionic strength conditions. Overall, it can be concluded that ChAld ligation to Lys residues at site L creates a hydrophobic tail at cytc, which promotes cytc anchoring to the membrane. Although not investigated in detail in this study, cytc adduction to cholesterol derived aldehydes could have implications in cytc release from mitochondria under apoptotic stimuli.
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo , São Paulo, SP, Brazil.
Thiago C
TC
Genaro-Mattos
Patricia P
PP
Appolinário
Katia C U
KC
Mugnol
Carlos
C
Bloch
Iseli L
IL
Nantes
Paolo
P
Di Mascio
Sayuri
S
Miyamoto
D000447:Aldehydes / Q000737:chemistry* / Q000633:toxicity; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D040761:Biomimetic Materials / Q000737:chemistry / Q000378:metabolism*; D002417:Cattle; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000737:chemistry*; D045304:Cytochromes c / Q000737:chemistry / Q000378:metabolism*; D004579:Electron Transport / Q000187:drug effects; D008027:Light; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism*; D008239:Lysine / Q000737:chemistry; D008928:Mitochondria / Q000378:metabolism*; D008958:Models, Molecular; D009206:Myocardium / Q000378:metabolism; D010084:Oxidation-Reduction; D010455:Peptides / Q000032:analysis / Q000737:chemistry; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D014357:Trypsin / Q000378:metabolism
D000447:Aldehydes; D008081:Liposomes; D010455:Peptides; D045304:Cytochromes c; D002784:Cholesterol; D014357:Trypsin; D008239:Lysine