Difference in the structures of alanine tri‐ and tetra‐peptides with antiparallel β‐sheet assessed by X‐ray diffraction,solid‐state NMR and chemical shift calculations by GIPAW |
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| Authors: | Tetsuo Asakura Koji Yazawa Kumiko Horiguchi Furitsu Suzuki Yusuke Nishiyama Katsuyuki Nishimura Hironori Kaji |
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| Affiliation: | 1. Department of Biotechnology, Tokyo University of Agriculture and Technology, Tokyo, Japan;2. Institute for Molecular Science, Japan;3. Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan;4. JEOL RESONANCE Inc., Akishima, Tokyo, Japan |
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| Abstract: | Alanine oligomers provide a key structure for silk fibers from spider and wild silkworms.We report on structural analysis of l ‐alanyl‐l ‐alanyl‐l ‐alanyl‐l ‐alanine (Ala)4 with anti‐parallel (AP) β‐structures using X‐ray and solid‐state NMR. All of the Ala residues in the (Ala)4 are in equivalent positions, whereas for alanine trimer (Ala)3 there are two alternative locations in a unit cell as reported previously (Fawcett and Camerman, Acta Cryst., 1975, 31, 658–665). (Ala)4 with AP β‐structure is more stable than AP‐(Ala)3 due to formation of the stronger hydrogen bonds. The intermolecular structure of (Ala)4 is also different from polyalanine fiber structure, indicating that the interchain arrangement of AP β‐structure changes with increasing alanine sequencelength. Furthermore the precise 1H positions, which are usually inaccesible by X‐ray diffraction method, are determined by high resolution 1H solid state NMR combined with the chemical shift calculations by the gauge‐including projector augmented wave method. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 13–20, 2014. |
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| Keywords: | solid state NMR alanine oligopeptide antiparallel β ‐sheet GIPAW |
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