title: NMR structures of a mitochondrial transit peptide from the green alga Chlamydomonas reinhardtii.
abstract: The 26-amino-acid pre-sequence of the ATP synthase beta subunit that directs the protein from the cytosol to mitochondria in the unicellular green alga Chlamydomonas reinhardtii has been synthesised and analysed using NMR spectroscopy/circular dichroism and compared to a chloroplast transit peptide from the same organism. The results demonstrate that the peptide, though mainly unstructured in water, undergoes a strong conformational change in a 36% water/64% 2,2,2-trifluoroethanol mixture. In this solvent condition, an alpha-helix was characterised by NMR from residue 2 to 26. Structure calculations under NMR restraints lead to a population of models of which 60% are kinked at position 9-10. Structural analysis indicates two hydrophobic sectors on the models with a discontinuity at the 9-10 kink level. The structures suggest a different interaction mode with the mitochondrial membrane compared to the chloroplast transit peptide.
authors.affiliation: Institut de Biologie Structurale CEA-CNRS, Grenoble, France. lancelin@ginko.cpe.fr
authors.forename: J M
authors.initials: JM
authors.lastname: Lancelin
authors.forename: P
authors.initials: P
authors.lastname: Gans
authors.forename: E
authors.initials: E
authors.lastname: Bouchayer
authors.forename: I
authors.initials: I
authors.lastname: Bally
authors.forename: G J
authors.initials: GJ
authors.lastname: Arlaud
authors.forename: J P
authors.initials: JP
authors.lastname: Jacquot
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000378:metabolism*; D002942:Circular Dichroism; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008928:Mitochondria / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000138:chemical synthesis / Q000737:chemistry; D017433:Protein Structure, Secondary; D006180:Proton-Translocating ATPases / Q000096:biosynthesis* / Q000138:chemical synthesis / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D046911:Macromolecular Substances; D011498:Protein Precursors; D006180:Proton-Translocating ATPases