NMR determination of the major solution conformation of a peptoid pentamer with chiral side chains

• DOI: 10.1073/pnas.95.8.4309
• Publication Date: 2002-07-26T14:40:11Z
• Authors: Philippe Armand; Kent Kirshenbaum; Richard A. Goldsmith; Shauna Farr-Jones; Annelise E. Barron; Kiet T. V. Truong; Ken A. Dill; Dale F. Mierke; Fred E. Cohen; Ronald N. Zuckermann; Erin K. Bradley
• Keywords: Peptoid; Side chain; Pentamer; Chromophore; Amide; Helix (gastropod); Polyproline helix; Chirality

Polymers of N-substituted glycines (“peptoids”) containing chiral centers at the α position their side chains can form stable structures in solution. We studied a prototypical peptoid, consisting five para -substituted ( S )- N -(1-phenylethyl)glycine residues, by NMR spectroscopy. Multiple configurational isomers were observed, but because extensive signal overlap, only major isomer all cis -amide bonds was examined detail. The data for this molecule, conjunction with previous CD spectroscopic results, indicate that species methanol is right-handed helix bonds. periodicity three residues per turn, pitch ≈6 Å. This conformation similar to anticipated computational studies peptoid octamer. helical repeat orients amide bond chromophores manner consistent intensity exhibited molecule. Many other polypeptoids have spectra, suggesting whole family peptoids capable adopting secondary structure motif. Taken together, our experimental and theoretical structural properties lay groundwork rational design more complex polypeptoid molecules, variety applications, ranging from nanostructures nonviral gene delivery systems.