Conformational studies on peptides of alpha-aminoxy acids with functionalized side-chains.
Peptides of homochiral alpha-aminoxy acids of nonpolar side chains can form a 1.8(8)-helix. In this paper, we report the conformational studies of alpha-aminoxy peptides 1-3, which have functionalized side chains, in both nonpolar and polar solvents. (1)H NMR, XRD, and FTIR absorption studies confirm the presence of the eight-membered-ring intramolecular hydrogen bonds (the N-O turns) in nonpolar solvents as well as in methanol. CD studies of peptides 1-3 in different solvents indicate that a substantial degree of helical content is retained in methanol and acidic aqueous buffers. The introduction of functionalized side chains in alpha-aminoxy peptides provides opportunities for designing biologically active peptides.
Yang
Dan
D
Department of Chemistry, Fudan University, Shanghai 200433, P.R. China. yangdan@hku.hk
Liu
Guo-Jun
GJ
Hao
Yu
Y
Li
Wei
W
Dong
Ze-Min
ZM
Zhang
Dan-Wei
DW
Zhu
Nian-Yong
NY
D000143:Acids / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry*; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D019906:Nuclear Magnetic Resonance, Biomolecular; D009842:Oligopeptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared
D000143:Acids; D000596:Amino Acids; D009842:Oligopeptides