Effect of one D‐Leu residue on right‐handed helical ‐L‐Leu‐Aib‐ peptides in the crystal state |
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| Authors: | Yosuke Demizu Mitsunobu Doi Yukiko Sato Masakazu Tanaka Haruhiro Okuda Masaaki Kurihara |
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| Affiliation: | 1. Division of Organic Chemistry, National Institute of Health Sciences, 1‐18‐1, Kamiyoga, Setagaya, Tokyo 158‐8501, Japan;2. Osaka University of Pharmaceutical Sciences, Osaka 569‐1094, Japan;3. Graduate School of Biomedical Sciences, Nagasaki University, 1‐14 Bunkyo‐machi, Nagasaki 852‐8521, Japan |
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| Abstract: | Four diastereomeric‐Leu‐Leu‐Aib‐Leu‐Leu‐Aib‐peptides, Boc‐D ‐Leu‐L ‐Leu‐Aib‐L ‐Leu‐L ‐Leu‐Aib‐OMe (1), Boc‐L ‐Leu‐D ‐Leu‐Aib‐L ‐Leu‐L ‐Leu‐Aib‐OMe (2), Boc‐L ‐Leu‐L ‐Leu‐Aib‐D ‐Leu‐L ‐Leu‐Aib‐OMe (3), and Boc‐L ‐Leu‐L ‐Leu‐Aib‐L ‐Leu‐D ‐Leu‐Aib‐OMe (4), were synthesized. The crystals of the four hexapeptides were characterized by X‐ray crystallographic analysis. Two diastereomeric hexapeptides 1 and 2 having D ‐Leu(1) or D ‐Leu(2) were folded into right‐handed (P) 3 10 ‐helical structures, while peptide 3 having D ‐Leu(4) was folded into a turn structure nucleated by type III′ and I$' bf{beta}$ ‐turns, and peptide 4 having D ‐Leu(5) was folded into a left‐handed (M) 3 10 ‐helical structure. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd. |
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| Keywords: | amino acids peptide X‐ray crystallographic analysis conformation secondary structure |
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