Helical Structures of Cyclopentene-based ?,?-Disubstituted ?-Amino Acid Homopeptides

Authors

  • Masakazu Tanaka Graduate School of Biomedical Sciences Nagasaki University, 1-14 Bunkyo-machi Nagasaki 852-8521, Japan;, Email: matanaka@nagasaki-u.ac.jp
  • Haruka Yakabi School of Pharmaceutical Sciences Nagasaki University, 1-14 Bunkyo-machi Nagasaki 852-8521, Japan
  • Haruki Nakatani School of Pharmaceutical Sciences Nagasaki University, 1-14 Bunkyo-machi Nagasaki 852-8521, Japan
  • Atsushi Ueda Graduate School of Biomedical Sciences Nagasaki University, 1-14 Bunkyo-machi Nagasaki 852-8521, Japan
  • Mitsunobu Doi Osaka University of Pharmaceutical Sciences Osaka 569-1094, Japan
  • Makoto Oba Graduate School of Biomedical Sciences Nagasaki University, 1-14 Bunkyo-machi Nagasaki 852-8521, Japan

DOI:

https://doi.org/10.2533/chimia.2018.848

Keywords:

Conformation, Cyclopentene, α,α-disubstituted α-amino acid, Helix, Peptide

Abstract

The cyclopentene-based ?,?-disubstituted ?-amino acid Ac5c= and its homopeptides, up to nonapeptides, were synthesized. The side-chain cyclopentene was expected to become symmetric, the C?-carbon to be puckered, and other C?, C?', C?, C?'-carbons to be coplanar. As expected, side-chain cyclopentene conformations became symmetric and C?-carbons were puckered. Conformational studies using FT-IR absorption, 1H NMR spectra, and X-ray crystallographic analyses revealed that Ac5c= homopeptides did not form a planar conformation, but assumed a 310-helical structure, similar to cyclopentane-based ?,?-disupstituted ?-amino acid homopeptides.

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Published

2018-12-19

How to Cite

[1]
M. Tanaka, H. Yakabi, H. Nakatani, A. Ueda, M. Doi, M. Oba, Chimia 2018, 72, 848, DOI: 10.2533/chimia.2018.848.