{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Mandal A"],"funding":["NCRR NIH HHS","NIEHS NIH HHS","NIAID NIH HHS","NHLBI NIH HHS","NIOSH CDC HHS","PHS HHS","NIGMS NIH HHS"],"pagination":["1873-84"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC4643272"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["109(9)"],"pubmed_abstract":["The cellular process of intrinsic apoptosis relies on the peroxidation of mitochondrial lipids as a critical molecular signal. Lipid peroxidation is connected to increases in mitochondrial reactive oxygen species, but there is also a required role for mitochondrial cytochrome c (cyt-c). In apoptotic mitochondria, cyt-c gains a new function as a lipid peroxidase that catalyzes the reactive oxygen species-mediated chemical modification of the mitochondrial lipid cardiolipin (CL). This peroxidase activity is caused by a conformational change in the protein, resulting from interactions between cyt-c and CL. The nature of the conformational change and how it causes this gain-of-function remain uncertain. Via a combination of functional, structural, and biophysical experiments we investigate the structure and peroxidase activity of cyt-c in its membrane-bound state. We reconstituted cyt-c with CL-containing lipid vesicles, and determined the increase in peroxidase activity resulting from membrane binding. We combined these assays of CL-induced proapoptotic activity with structural and dynamic studies of the membrane-bound protein via solid-state NMR and optical spectroscopy. Multidimensional magic angle spinning (MAS) solid-state NMR of uniformly (13)C,(15)N-labeled protein was used to detect site-specific conformational changes in oxidized and reduced horse heart cyt-c bound to CL-containing lipid bilayers. MAS NMR and Fourier transform infrared measurements show that the peripherally membrane-bound cyt-c experiences significant dynamics, but also retains most or all of its secondary structure. Moreover, in two-dimensional and three-dimensional MAS NMR spectra the CL-bound cyt-c displays a spectral resolution, and thus structural homogeneity, that is inconsistent with extensive membrane-induced unfolding. Cyt-c is found to interact primarily with the membrane interface, without significantly disrupting the lipid bilayer. Thus, membrane binding results in cyt-c gaining the increased peroxidase activity that represents its pivotal proapoptotic function, but we do not observe evidence for large-scale unfolding or penetration into the membrane core."],"journal":["Biophysical journal"],"pubmed_title":["Structural Changes and Proapoptotic Peroxidase Activity of Cardiolipin-Bound Mitochondrial Cytochrome c."],"pmcid":["PMC4643272"],"funding_grant_id":["U19 AI068021","R01 OH008282","HL114453","U19 AIO68021","R01 ES020693","ES020693","T32 GM088119","OH008282","P01 HL114453","UL1 RR024153"],"pubmed_authors":["Kagan VE","Ahn J","DeLucia M","Kodali R","Hoop CL","Mandal A","van der Wel PC"],"additional_accession":[]},"is_claimable":false,"name":"Structural Changes and Proapoptotic Peroxidase Activity of Cardiolipin-Bound Mitochondrial Cytochrome c.","description":"The cellular process of intrinsic apoptosis relies on the peroxidation of mitochondrial lipids as a critical molecular signal. Lipid peroxidation is connected to increases in mitochondrial reactive oxygen species, but there is also a required role for mitochondrial cytochrome c (cyt-c). In apoptotic mitochondria, cyt-c gains a new function as a lipid peroxidase that catalyzes the reactive oxygen species-mediated chemical modification of the mitochondrial lipid cardiolipin (CL). This peroxidase activity is caused by a conformational change in the protein, resulting from interactions between cyt-c and CL. The nature of the conformational change and how it causes this gain-of-function remain uncertain. Via a combination of functional, structural, and biophysical experiments we investigate the structure and peroxidase activity of cyt-c in its membrane-bound state. We reconstituted cyt-c with CL-containing lipid vesicles, and determined the increase in peroxidase activity resulting from membrane binding. We combined these assays of CL-induced proapoptotic activity with structural and dynamic studies of the membrane-bound protein via solid-state NMR and optical spectroscopy. Multidimensional magic angle spinning (MAS) solid-state NMR of uniformly (13)C,(15)N-labeled protein was used to detect site-specific conformational changes in oxidized and reduced horse heart cyt-c bound to CL-containing lipid bilayers. MAS NMR and Fourier transform infrared measurements show that the peripherally membrane-bound cyt-c experiences significant dynamics, but also retains most or all of its secondary structure. Moreover, in two-dimensional and three-dimensional MAS NMR spectra the CL-bound cyt-c displays a spectral resolution, and thus structural homogeneity, that is inconsistent with extensive membrane-induced unfolding. Cyt-c is found to interact primarily with the membrane interface, without significantly disrupting the lipid bilayer. Thus, membrane binding results in cyt-c gaining the increased peroxidase activity that represents its pivotal proapoptotic function, but we do not observe evidence for large-scale unfolding or penetration into the membrane core.","dates":{"release":"2015-01-01T00:00:00Z","publication":"2015 Nov","modification":"2026-05-05T09:58:45.57Z","creation":"2019-03-27T02:01:51Z"},"accession":"S-EPMC4643272","cross_references":{"pubmed":["26536264"],"doi":["10.1016/j.bpj.2015.09.016"]}}