Topological Study of the Structures of Heterochiral Peptides Containing Equal Amounts of l-Leu and d-Leu.
We designed and synthesized two dodecapeptides, Boc-(l-Leu-l-Leu-Aib-d-Leu-d-Leu-Aib)2-OMe (5) and Boc-l-Leu-l-Leu-Aib-(d-Leu-d-Leu-Aib)2-l-Leu-l-Leu-Aib-OMe (6), that contain equal amounts of l-Leu, d-Leu, and achiral Aib residues. The conformations of peptides 5 and 6 in the crystalline state were studied using X-ray crystallographic analysis. Peptide 5 formed a left-handed (M) α-helical structure, whereas peptide 6 was composed of a combination of fused (M) α-helical and right-handed (P) 310-helical structures. In solution, roughly equivalent amounts of (P) and (M) helices were present in 5, whereas the (M) α-helix was present in 6 as its dominant conformation.
Division of Organic Chemistry, National Institute of Health Sciences , Tokyo 158-8501, Japan.
Yosuke
Y
Demizu
Division of Organic Chemistry, National Institute of Health Sciences , Tokyo 158-8501, Japan.|Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology , Yokohama 226-8501, Japan.
Hiroko
H
Yamashita
Osaka University of Pharmaceutical Sciences , Osaka 569-1094, Japan.
Mitsunobu
M
Doi
Division of Organic Chemistry, National Institute of Health Sciences , Tokyo 158-8501, Japan.
Takashi
T
Misawa
Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki 852-8521, Japan.
Makoto
M
Oba
Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki 852-8521, Japan.
Masakazu
M
Tanaka
Division of Organic Chemistry, National Institute of Health Sciences , Tokyo 158-8501, Japan.|Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology , Yokohama 226-8501, Japan.
Masaaki
M
Kurihara
D018360:Crystallography, X-Ray; D004151:Dipeptides / Q000737:chemistry*; D007930:Leucine / Q000737:chemistry*; D008958:Models, Molecular; D009842:Oligopeptides / Q000737:chemistry*; D011487:Protein Conformation; D013237:Stereoisomerism
D004151:Dipeptides; D009842:Oligopeptides; C045139:leucyl-leucine-methyl ester; C038361:leucylleucine; D007930:Leucine