Folding propensity of cyclohexylether-delta-peptides.
[structure: see text] Linear (n = 2-18) and cyclic oligomers (n = 3-8) of a cyclohexylether-delta-amino acid (COA) were prepared in high yield and stereopurity. CD spectra of the linear oligomers were indicative of secondary structure formation. X-ray crystal structures of cyclic COA oligomers revealed hydrophobic packing and internal 5- and 10-membered-ring hydrogen bonds. Ether and amide oxygens reside preferably in an ap orientation. This conformational locking is apparently broken by a C-2 substituent in an asymmetric cyclotrimer, for which a zeolithe-like tubular structure was found.
Arndt
Hans-Dieter
HD
Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Str. 2, D-12489 Berlin, Germany.
Ziemer
Burkhard
B
Koert
Ulrich
U
D000596:Amino Acids / Q000737:chemistry; D018360:Crystallography, X-Ray; D004988:Ethers, Cyclic / Q000737:chemistry*; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D013816:Thermodynamics
D000596:Amino Acids; D004988:Ethers, Cyclic; D010456:Peptides, Cyclic