title: Secondary structure of a mitochondrial signal peptide in lipid bilayer membranes.
abstract: The secondary structure of the synthetic signal peptide of cytochrome c oxidase subunit IV (coxIV-25) has been measured by circular dichroism spectroscopy in different lipid environments. CoxIV-25 is polymorphic in membranes. It forms an amphiphilic alpha-helix both in negatively charged lipid bilayers (up to 49% helix) and in detergent micelles (up to 42% helix). In association with bilayers of the zwitterionic lipid phosphatidylcholine, coxIV-25 takes an aperiodic, unidentified structure. CoxIV-25 is also partially alpha-helical in bilayers of cardiolipin, mitochondrial lipid extracts and mixtures of synthetic phosphatidylcholine and phosphatidylglycerol.
authors.affiliation: Department of Biophysical Chemistry, University of Basel, Switzerland.
authors.forename: L K
authors.initials: LK
authors.lastname: Tamm
authors.forename: I
authors.initials: I
authors.lastname: Bartoldus
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002308:Cardiolipins / Q000494:pharmacology; D002417:Cattle; D002942:Circular Dichroism; D003576:Electron Transport Complex IV / Q000737:chemistry*; D008051:Lipid Bilayers / Q000032:analysis*; D008563:Membrane Lipids / Q000032:analysis* / Q000494:pharmacology; D008929:Mitochondria, Heart / Q000737:chemistry*; D008969:Molecular Sequence Data; D010713:Phosphatidylcholines / Q000494:pharmacology; D010715:Phosphatidylglycerols / Q000494:pharmacology; D011487:Protein Conformation / Q000187:drug effects; D021382:Protein Sorting Signals / Q000737:chemistry*
chemical_list: D002308:Cardiolipins; D008051:Lipid Bilayers; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D021382:Protein Sorting Signals; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; D003576:Electron Transport Complex IV; C028694:1-palmitoyl-2-oleoylphosphatidylcholine