Synthesis and conformational studies of gamma-aminoxy peptides.
We have synthesized a series of gamma-aminoxy acids, including unsubstituted and gamma4-Ph-, gamma4-alkyl-, and gamma(3,4)-cyclohexyl-substituted systems. Coupling of these monomers to oligomers can be realized using EDCI/HOBt (or HOAt) as the coupling agent. gamma-Aminoxy peptides can form 10-membered-ring intramolecular hydrogen bonds-so-called "gamma N-O turns"-between adjacent residues, the extent of which is controlled by the nature of the side chain of each gamma-aminoxy acid residue, increasing from the unsubstituted gamma-aminoxy peptide to the gamma4-alkyl aminoxy peptides to the gamma4-phenyl- and gamma(3,4)-cyclohexyl-substituted aminoxy peptides. The presence of two consecutive homochiral 10-membered-ring intramolecular hydrogen bonds leads to the formation of a novel helical structure. Theoretical studies on a series of model peptides rationalize very well the experimentally observed conformational features of these gamma-aminoxy peptides.
Chen
Fei
F
Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China.
Song
Ke-Sheng
KS
Wu
Yun-Dong
YD
Yang
Dan
D
D000596:Amino Acids / Q000737:chemistry*; D002942:Circular Dichroism; D006860:Hydrogen Bonding; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013055:Spectrophotometry, Infrared
D000596:Amino Acids; D009842:Oligopeptides