title: Comparison of p25 presequence peptide and melittin. Red blood cell haemolysis and band 3 aggregation.
abstract: The 25 residue presequence (p25) for subunit IV of yeast cytochrome oxidase had previously been shown to possess structural and behavioural characteristics in common with the bee venom polypeptide, melittin. The present study extends the results of leakage experiments on model-membrane systems to the haemolysis of human erythrocytes, which both peptides are shown to accomplish in a manner sensitive to membrane potential. In addition, the laser flash-induced transient dichroism technique for measuring protein rotational diffusion has been used to show that both peptides aggregate band 3, the major integral membrane protein of the erythrocyte. Aggregation cannot be reversed by high ionic strength; this serves to differentiate these peptides from other positively charged species such as polylysine that aggregate band 3 at low ionic strength. These results suggest that aggregation of membrane proteins may possibly prove to be a feature of the interaction of p25 signal peptide with mitochondrial membranes.
authors.affiliation: Department of Chemistry and Biological Chemistry, University of Essex, Colchester, U.K.
authors.forename: M J
authors.initials: MJ
authors.lastname: Clague
authors.forename: R J
authors.initials: RJ
authors.lastname: Cherry
mesh_terms: D000595:Amino Acid Sequence; D001514:Bee Venoms / Q000494:pharmacology; D002942:Circular Dichroism; D003576:Electron Transport Complex IV / Q000494:pharmacology; D004792:Enzyme Precursors / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects*; D006801:Humans; D046911:Macromolecular Substances; D008555:Melitten / Q000494:pharmacology; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000494:pharmacology
chemical_list: D001514:Bee Venoms; D004792:Enzyme Precursors; D046911:Macromolecular Substances; D021382:Protein Sorting Signals; D008555:Melitten; D003576:Electron Transport Complex IV