A synthetic peptidoglycan fragment as a competitive inhibitor of the melanization cascade

Won Park Ji, Byung Rok Je, Shunfu Piao, Seiichi Inamura, Yukari Fujimoto, Koichi Fukase, Shoichi Kusumoto, Kenneth Söderhäll, Nam Chul Ha, Bok Luel Lee

研究成果: Article査読

45 被引用数 (Scopus)


Melanin synthesis is essential for defense and development but must be tightly controlled because systemic hyperactivation of the prophenoloxidase and excessive melanin synthesis are deleterious to the hosts. The melanization cascade of the arthropods can be activated by bacterial lysine-peptidoglycan (PGN), diaminopimelic acid (DAP)-PGN, or fungal β-1,3-glucan. The molecular mechanism of how DAP- or Lys-PGN induces melanin synthesis and which molecules are involved in distinguishing these PGNs are not known. The identification of PGN derivatives that can work as inhibitors of the melanization cascade and the characterization of PGN recognition molecules will provide important information to clarify how the melanization is regulated and controlled. Here, we report that a novel synthetic Lys-PGN fragment ((GlcNAc-Mur-NAc-L-Ala-D-isoGln-L-Lys-D- Ala)2, T-4P2) functions as a competitive inhibitor of the natural PGN-induced melanization reaction. By using a T-4P2-coupled column, we purified the Tenebrio molitor PGN recognition protein (Tm-PGRP) without causing activation of the prophenoloxidase. The purified Tm-PGRP recognized both Lys- and DAP-PGN. In vitro reconstitution experiments showed that Tm-PGRP functions as a common recognition molecule of Lys- and DAP-PGN-dependent melanization cascades.

ジャーナルJournal of Biological Chemistry
出版ステータスPublished - 2006 3月 24

ASJC Scopus subject areas

  • 生化学
  • 分子生物学
  • 細胞生物学


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