title: One-handed helical screw direction of homopeptide foldamer exclusively induced by cyclic α-amino acid side-chain chiral centers.
abstract: Chiral cyclic α,α-disubstituted amino acids, (3S,4S)- and (3R,4R)-1-amino-3,4-(dialkoxy)cyclopentanecarboxylic acids ((S,S)- and (R,R)-Ac(5)c(dOR); R: methyl, methoxymethyl), were synthesized from dimethyl L-(+)- or D-(-)-tartrate, and their homochiral homoligomers were prepared by solution-phase methods. The preferred secondary structure of the (S,S)-Ac(5)c(dOMe) hexapeptide was a left-handed (M) 3(10) helix, whereas those of the (S,S)-Ac(5)c(dOMe) octa- and decapeptides were left-handed (M) α helices, both in solution and in the crystal state. The octa- and decapeptides can be well dissolved in pure water and are more α helical in water than in 2,2,2-trifluoroethanol solution. The left-handed (M) helices of the (S,S)-Ac(5)c(dOMe) homochiral homopeptides were exclusively controlled by the side-chain chiral centers, because the cyclic amino acid (S,S)-Ac(5)c(dOMe) does not have an α-carbon chiral center but has side-chain γ-carbon chiral centers.
authors.affiliation: National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Demizu
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Doi
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kurihara
authors.forename: Tokumi
authors.initials: T
authors.lastname: Maruyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suemune
authors.forename: Masakazu
authors.initials: M
authors.lastname: Tanaka
mesh_terms: D000598:Amino Acids, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry*; D013237:Stereoisomerism; D014270:Trifluoroethanol / Q000737:chemistry*
chemical_list: D000598:Amino Acids, Cyclic; D010455:Peptides; D012996:Solutions; D014270:Trifluoroethanol