(S)-C alpha-ethyl, C alpha-benzylglycine [(S)-(alpha Et)Phe] peptides fold in left-handed helical structures.
The first x-ray diffraction structure analysis of a C alpha-ethyl, C alpha-benzylglycine [(alpha Et)Phe]-containing peptide, N alpha-benzyloxycarbonyl-alpha-aminoisobutyryl-alpha-amino-isobutyr yl-(S)- C alpha-benzylglycyl-alpha-aminoisobutyric acid (methanol solvate), has been performed. In the crystal state the N alpha-protected tetrapeptide is folded in an incipient, left-handed 3(10)-helical structure. This finding confirms that the relationship between (alpha Et)Phe alpha-carbon chirality and screw sense of the helix that is formed is opposite to that exhibited by protein amino acids, including Phe.
Doi
M
M
Osaka University of Pharmaceutical Sciences, Japan.
Ishida
T
T
Polese
A
A
Formaggio
F
F
Crisma
M
M
Toniolo
C
C
Broxterman
Q B
QB
Kamphuis
J
J
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009842:Oligopeptides / Q000737:chemistry*; D017510:Protein Folding; D017433:Protein Structure, Secondary
D009842:Oligopeptides; C098300:benzyloxycarbonyl-aminoisobutyryl-aminoisobutyryl-(alpha-ethyl)phenylalanyl-aminoisobutyric acid