title: Slow tert-butyl ester acidolysis and peptide 3(10)-helix to alpha-helix transition in HFIP solution.
abstract: We have already shown by CD and NMR techniques that the terminally protected homo-octapeptides Z (and Ac)-[L-(alphaMe)Val](8)-OtBu undergo a slow and irreversible 3(10)-helix to alpha-helix transition when dissolved in 1,1,1,3,3,3-hexafluoroisopropanol. In the present work, we find by HPLC and CD that under the aforementioned experimental conditions, a slow acidolysis of the tert-butyl ester functionality does take place affording the corresponding octapeptide free acids. The results of our combined chromatographic and spectroscopic experiments are confirmed by a comparison with the properties of independently synthesized and chemically characterized authentic compounds.
authors.affiliation: Department of Chemistry, Institute of Biomolecular Chemistry, CNR, University of Padova, Padova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Moretto
authors.forename: Marco
authors.initials: M
authors.lastname: Crisma
authors.forename: Fernando
authors.initials: F
authors.lastname: Formaggio
authors.forename: Bernard
authors.initials: B
authors.lastname: Kaptein
authors.forename: Quirinus B
authors.initials: QB
authors.lastname: Broxterman
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Keiderling
authors.forename: Claudio
authors.initials: C
authors.lastname: Toniolo
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004952:Esters / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D010455:Peptides / Q000737:chemistry*; D020005:Propanols; D017433:Protein Structure, Secondary; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D006845:Hydrocarbons, Fluorinated
chemical_list: D004952:Esters; D010455:Peptides; D020005:Propanols; D012996:Solutions; C001337:hexafluoroisopropanol; D006845:Hydrocarbons, Fluorinated