title: Backbone resonance assignments of ferric human cytochrome c and the pro-apoptotic G41S mutant in the ferric and ferrous states.
abstract: Human cytochrome c is a multi-functional protein with key roles in both the mitochondrial electron transfer chain and in apoptosis. In the latter, a complex formed between the mitochondrial phospholipid cardiolipin and cytochrome c is crucial for instigating the release of pro-apoptotic factors, including cytochrome c, from the mitochondrion into the cytosol. The G41S mutant of human cytochrome c is the only known disease-related variant of cytochrome c and causes increased apoptotic activity in patients with autosomal dominant thrombocytopenia. NMR spectroscopy can be used to investigate the interaction of human cytochrome c with cardiolipin and the structural and dynamic factors, which may contribute to enhanced apoptotic activity for the G41S mutant. We present here essentially full backbone amide resonance assignments for ferric human cytochrome c (98 %) as well as assignments of both the ferric (92 %) and ferrous (95 %) forms of the G41S mutant. Backbone amide chemical shift differences between the wild type and G41S mutant in the ferric state reveals significant changes around the mutation site, with many other amides also affected. This suggests the possibility of increased dynamics and/or a change in the paramagnetic susceptibility tensor of the G41S mutant relative to the wild type protein.
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK.
authors.forename: Andreas Ioannis
authors.initials: AI
authors.lastname: Karsisiotis
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK.
authors.forename: Oliver M
authors.initials: OM
authors.lastname: Deacon
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK.
authors.forename: Badri S
authors.initials: BS
authors.lastname: Rajagopal
authors.affiliation: School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Macdonald
authors.affiliation: School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
authors.forename: Tharin M A
authors.initials: TM
authors.lastname: Blumenschein
authors.affiliation: School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
authors.forename: Geoffrey R
authors.initials: GR
authors.lastname: Moore
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK. jworrall@essex.ac.uk.
authors.forename: Jonathan A R
authors.initials: JA
authors.lastname: Worrall
mesh_terms: D017209:Apoptosis; D045304:Cytochromes c / Q000737:chemistry*; D006801:Humans; D007501:Iron / Q000737:chemistry*; D050505:Mutant Proteins / Q000737:chemistry*; D009154:Mutation / Q000235:genetics; D019906:Nuclear Magnetic Resonance, Biomolecular; D066244:Proton Magnetic Resonance Spectroscopy
chemical_list: D050505:Mutant Proteins; D045304:Cytochromes c; D007501:Iron
keywords: Apoptosis; Human cytochrome c; Mitochondria; Paramagnetic NMR