title: 4-Cyano-α-methyl-l-phenylalanine as a spectroscopic marker for the investigation of peptaibiotic-membrane interactions.
abstract: Two analogs of the ten-amino acid residue, membrane-active lipopeptaibiotic trichogin GA IV, mono-labeled with 4-cyano-α-methyl-L-phenylalanine, a potentially useful fluorescence and IR absorption probe of the local microenvironment, were synthesized by the solid-phase methodology and conformationally characterized. The single modification was incorporated either at the N-terminus (position 1) or near the C-terminus (position 8) of the peptide main chain. In both cases, the replaced amino acid was the equally helicogenic α-aminoisobutyric acid (Aib) residue. We performed a solution conformational analysis by use of FT-IR absorption, CD, and 2D-NMR spectroscopies. The results indicate that both labeled analogs essentially maintain the overall helical propensity of the naturally occurring lipopeptaibiotic. Peptide-membrane interactions were assessed by fluorescence and ATR-IR absorption techniques. Analogies and differences between the two peptides were highlighted. Taken together, our data confirm literature results that some of the spectroscopic parameters of the 4-cyanobenzyl chromophore are sensitive markers of the local microenvironment.
authors: ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, IT-35131 Padova.
authors: Marta
authors: M
authors: De Zotti
authors: Sara
authors: S
authors: Bobone
authors: Annalisa
authors: A
authors: Bortolotti
authors: Edoardo
authors: E
authors: Longo
authors: Barbara
authors: B
authors: Biondi
authors: Cristina
authors: C
authors: Peggion
authors: Fernando
authors: F
authors: Formaggio
authors: Claudio
authors: C
authors: Toniolo
authors: Andrea
authors: A
authors: Dalla Bona
authors: Bernard
authors: B
authors: Kaptein
authors: Lorenzo
authors: L
authors: Stella
mesh_terms: D000621:Aminoisobutyric Acids / Q000737:chemistry; D002462:Cell Membrane / Q000737:chemistry*; D002942:Circular Dichroism; D055666:Lipopeptides / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009570:Nitriles / Q000138:chemical synthesis / Q000737:chemistry*; D010455:Peptides / Q000032:analysis / Q000737:chemistry*; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D060327:Solid-Phase Synthesis Techniques; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: C000607295:4-cyano-alpha-methylphenylalanine; D000621:Aminoisobutyric Acids; D055666:Lipopeptides; D009570:Nitriles; D010455:Peptides; C116419:trichogin GA IV; C100049:2-aminoisobutyric acid; D010649:Phenylalanine
keywords: L-Phenylalanine, 4-cyano-α-methyl-; Membrane activity; Peptaibols; Solid-phase synthesis