Trishomocubane amino acid as a beta-turn scaffold.
The synthesis and X-ray structure of two diasteriomeric heptapeptides [Ac-Ala-Ala-Ala-(R/S)-Cage-Ala-Ala-Ala-NH2] with a trishomocubane amino acid as a beta-turn scaffold are reported. The amino acid was synthesized as a racemate and two diastereomeric peptides were obtained. The two peptides were separated by preparative high-pressure liquid chromatography and crystals suitable for X-ray analysis were grown for both diasteriomeric peptides. In general, both the peptides satisfy the criteria for beta-turn conformations. Five of the six Ala residues of both cage peptide crystals satisfy the criteria for 3(10)-helix characteristics and the cage amino acid residue satisfied the alpha-helix classification. These experimental results confirm previous theoretical studies in our laboratory which predicted that the cage moiety would be a strong/active beta-turn inducer.
Albericio
Fernando
F
Department of Organic Chemistry, University of Barcelona, Barcelona 08028, Spain.
Arvidson
Per I
PI
Bisetty
Krishna
K
Giralt
Ernest
E
Govender
Thavendran
T
Jali
Samuel
S
Kongsaeree
Palangpon
P
Kruger
Hendrik G
HG
Prabpai
Samran
S
D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D018716:Molecular Mimicry; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013237:Stereoisomerism
D000596:Amino Acids; D009842:Oligopeptides