title: Total syntheses in solution of TOAC-labelled alamethicin F50/5 analogues.
abstract: Total syntheses in solution of a set of four selected analogues of the 19-mer component F50/5 of alamethicin, the most extensively studied among the channel-former peptaibol antibiotics, are planned and reported. All analogues bear three Glu(OMe) residues, replacing the Gln residues at positions 7, 18, and 19 of the naturally occurring compound. Three analogues are mono-labelled with the free-radical-containing amino acid residue TOAC at the strategic positions 1, 8, or 16. The fourth analogue is bis-labelled with the same EPR-active residue at both positions 1 and 16. In the native sequence, all of the positions where TOAC replacements have been introduced are characterized by residues of Aib, the prototype of the class of helicogenic C(alpha)-tetrasubstituted alpha-amino acids. All of the TOAC analogues synthesized exhibit significant membrane-modifying properties.
authors.affiliation: Institute of Biomolecular Chemistry, Padova Unit, CNR, Department of Chemistry, University of Padova, Padova, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Peggion
authors.forename: Micha
authors.initials: M
authors.lastname: Jost
authors.forename: Chiara
authors.initials: C
authors.lastname: Baldini
authors.forename: Fernando
authors.initials: F
authors.lastname: Formaggio
authors.forename: Claudio
authors.initials: C
authors.lastname: Toniolo
mesh_terms: D000408:Alamethicin / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry; D000595:Amino Acid Sequence; D003497:Cyclic N-Oxides / Q000737:chemistry*; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012996:Solutions
chemical_list: D003497:Cyclic N-Oxides; D012996:Solutions; D000408:Alamethicin; C037109:2,2,6,6-tetramethylpiperidine-N-oxide-4-amino-4-carboxylic acid