title: Folding of a linear array of α-amino acids within a helical aromatic oligoamide frame.
abstract: Control of the spatial organization of proteinogenic side chains is critical for the development of protein mimics with selective recognition properties toward target protein surfaces. We present a novel methodology for producing a linear array of proteinogenic residues based on the incorporation of α-amino acids into sequences of rigid, helically folded oligoamides of 8-amino-2-quinolinecarboxylic acid (Q). When L-leucine (L) was alternated with dimer Q2, the resulting sequence adopted a right-handed helical conformation, as deduced in solution from the CD spectra of L-(LQ2)n (n = 2, 4) and in the solid state from X-ray crystallographic analysis of (±)-(LQ2)4. Each LQ2 segment spanned just one helix turn (pitch of 3.5 Å), and consequently, the four leucine side chains of (LQ2)4 formed a linear array. In solution, NMR analysis showed that both L-(LQ2)2 and L-(LQ2)4 exist as a mixture of two slowly equilibrating folded conformers, the proportion of which strongly varies with the solvent.
authors.affiliation: Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Kudo
authors.forename: Victor
authors.initials: V
authors.lastname: Maurizot
authors.forename: Brice
authors.initials: B
authors.lastname: Kauffmann
authors.forename: Aya
authors.initials: A
authors.lastname: Tanatani
authors.forename: Ivan
authors.initials: I
authors.lastname: Huc
mesh_terms: D000577:Amides / Q000737:chemistry*; D007930:Leucine / Q000737:chemistry*; D015394:Molecular Structure; D011804:Quinolines / Q000737:chemistry*
chemical_list: C558648:8-amino-2-quinoline carboxylic acid; D000577:Amides; D011804:Quinolines; D007930:Leucine