Structural investigation of "cis" and "trans" vinylogous peptides: cis-vinylog turn in folded cis-vinylogous peptides, an excellent mimic of the natural beta-turn.
[structure: see text] Various sequences of modified peptides including those containing a cis- or trans-vinylogous residue have been studied using X-ray diffraction in the solid state and 1H NMR and IR spectroscopy in solution. A cis-vinylogous residue promotes an NH to CO intramolecular H-bond, closing a nine-membered pseudocycle that stabilizes a folded moiety that we proposed to name the cis-vinylogous turn. A trans-vinylogous residue involves an extended conformation. Two consecutive vinylogous residues retain their own structural propensity: "Xaa(tr)"-"Xaa(cis)" or "Xaa(cis)"-"Xaa(tr)" sequence is singly folded, whereas "Xaa(cis)"-"Xaa(cis)" sequence is doubly folded. Oligo vinylogs with all-trans or all-cis or alternating cis-trans motifs could constitute new classes of foldamers.
Grison
Claude
C
UMR 7565 CNRS-Université Henri Poincaré, Nancy 1, BP 239, 54506 Vandoeuvre-les-Nancy, France. cgrison@univ-montp2.fr
Coutrot
Philippe
P
Genève
Stéphane
S
Didierjean
Claude
C
Marraud
Michel
M
D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D018716:Molecular Mimicry; D010455:Peptides / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
D010455:Peptides