Scholarlink

<p>Kunitz-type protease inhibitors are well-known protease inhibitors found in various organisms, consisting of approximately 60 amino acid residues and featuring three disulfide bridges with a unique cysteine (Cys) framework. Among venomous animals, KTTs inhibit voltage-gated ion channels. In this study, we identified eight novel KTTs in the TTX-bearing flatworm <i>Planocera multitentaculata</i>, naming them <i>Pm</i>-KTT-1 through -8. These <i>Pm</i>-KTTs share 37.9–46.5% amino acid sequence identities with BPTI and DTX-K. Additionally, since <i>Pm</i>-KTTs contained conserved amino acid residues involved in the inhibition of trypsin and potassium channels, we speculated that <i>Pm</i>-KTTs act as inhibitors of trypsin and potassium channels. Recombinant expression of <i>Pm</i>-KTT-1 through -5 inhibited trypsin activity. Moreover, <i>Pm</i>-KTT-4 regulated <i>Drosophila</i> K<sup>+</sup> channels in <i>Shaker</i> and <i>Shal.</i> Furthermore, <i>Pm</i>-KTT-4 functioned as a gating modifier, unlike typical KTTs in other venomous animals. These findings provide the first molecular and functional characterization of toxic polypeptides in <i>P. multitentaculata</i>, expanding our understanding of the evolutionary diversity and biological roles of Kunitz-type toxins.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Discovery and Functional Characterization of Kunitz-Type Toxins from the Tetrodotoxin-Bearing Flatworm Planocera Multitencaculata

  • 期刊论文

  • 发表日期：

    2026年1月6日

查看全文
  • Hikaru Oyama,
  • Hidetoshi Inagaki

摘要

Kunitz-type protease inhibitors are well-known protease inhibitors found in various organisms, consisting of approximately 60 amino acid residues and featuring three disulfide bridges with a unique cysteine (Cys) framework. Among venomous animals, KTTs inhibit voltage-gated ion channels. In this study, we identified eight novel KTTs in the TTX-bearing flatworm Planocera multitentaculata, naming them Pm-KTT-1 through -8. These Pm-KTTs share 37.9–46.5% amino acid sequence identities with BPTI and DTX-K. Additionally, since Pm-KTTs contained conserved amino acid residues involved in the inhibition of trypsin and potassium channels, we speculated that Pm-KTTs act as inhibitors of trypsin and potassium channels. Recombinant expression of Pm-KTT-1 through -5 inhibited trypsin activity. Moreover, Pm-KTT-4 regulated Drosophila K+ channels in Shaker and Shal. Furthermore, Pm-KTT-4 functioned as a gating modifier, unlike typical KTTs in other venomous animals. These findings provide the first molecular and functional characterization of toxic polypeptides in P. multitentaculata, expanding our understanding of the evolutionary diversity and biological roles of Kunitz-type toxins.