Role of positions e and g in the fibrous assembly formation of an amphipathic α-helix-forming polypeptide

Toshiaki Takei, Kouhei Tsumoto*, Masakuni Yoshino, Shuichi Kojima, Kazumori Yazaki, Takuya Ueda, Tsunetomo Takei, Fumio Arisaka, Kin Ichiro Miura

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


We previously characterized α3, a polypeptide that has a three times repeated sequence of seven amino acids (abcdefg: LETLAKA) and forms fibrous assemblies composed of amphipathic a-helices. Upon comparison of the amino acid sequences of α3 with other a-helix forming polypeptides, we proposed that the fibrous assemblies were formed due to the alanine (Ala) residues at positions e and g. Here, we characterized seven α3 analog polypeptides with serine (Ser), glycine (Gly), or charged residues substituted for Ala at positions e and g. The α-helix forming abilities of the substituted polypeptides were less than that of α3. The polypeptides with amino acid substitutions at position g and the polypeptide KEα3, in which Ala was substituted with charged amino acids, formed few fibrous assemblies. In contrast, polypeptides with Ala replaced by Ser at position e formed β-sheets under several conditions. These results show that Ala residues at position e and particularly at position g are involved in the formation of fibrous assemblies.

Original languageEnglish
Pages (from-to)260-272
Number of pages13
JournalBiopolymers - Peptide Science Section
Issue number3
Publication statusPublished - 2014 May 1
Externally publishedYes


  • Aggregation
  • Amphipathic α-helix
  • Fibrous assembly
  • Self-assembly

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Biomaterials
  • Organic Chemistry


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