Conformational behavior of Cα,α-diphenyl glycine: Extended conformation in tripeptides containing consecutive Dϕg residues

✍ Scribed by Vincenzo Pavone; Angela Lombardi; Michele Saviano; Giuseppina De Simone; Flavia Nastri; Ornella Maglio; Yuichiro Omote; Yoshinori Yamanaka; Takashi Yamada

• Publisher: Wiley (John Wiley & Sons)
• Year: 2000
• Tongue: English
• Weight: 187 KB
• Volume: 53
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/(sici)1097-0282(200002)53:2<161::aid-bip6>3.0.co;2-5

✦ Synopsis

Recent studies on the conformational preferences of the Dg (C ␣,␣ -diphenylglycine) residue showed that this C ␣,␣ -disubstituted glycine has a structural versatility. In fact, depending on the nature of the following or preceding residue, Dg can assume either folded or extended conformations. We have carried out the analysis of the conformational preferences of the Dg residue in tripeptides containing consecutive Dg residues. The crystal structures of Z-Dg-Dg-Dg-OMe (a; Z ϭ benzyloxycarbonyl; OMe ϭ methyl ester), Z-Aib-Dg-Dg-OMe (b; Aib ϭ ␣-aminoisobutyric acid), and Z-Ac 3 c-Dg-Dg-OMe (c; Ac 3 c ϭ ␣-amino-cyclopropan carboxylic acid), are here reported. The Dg residues adopt the fully extended conformation in the three tripeptides examined. Together with our previous findings on Dg containing peptides, the structures of the peptides here examined, indicate that the presence of adjacent Dg residue in the sequence further stabilizes the extended conformation.