Tachylectin-2: Crystal structure of a specific GlcNAc/GalNAc-binding lectin involved in the innate immunity host defense of the Japanese horseshoe crab Tachypleus tridentatus

Hans Georg Beisel, Shun Ichiro Kawabata, Sadaaki Iwanaga, Robert Huber, Wolfram Bode

研究成果: ジャーナルへの寄稿学術誌査読

144 被引用数 (Scopus)

抄録

Tachylectin-2, isolated from large granules of the hemocytes of the Japanese horseshoe crab (Tachypleus tridentatus), is a 236 amino acid protein belonging to the lectins. It binds specifically to N-acetylglucosamine and N-acetylgalactosamine and is a part of the innate immunity host defense system of the horseshoe crab. The X-ray structure of tachylectin-2 was solved at 2.0 Å resolution by the multiple isomorphous replacement method and this molecular model was employed to solve the X-ray structure of the complex with N-acetylglucosamine. Tachylectin-2 is the first protein displaying a five-bladed β-propeller structure. Five four-stranded antiparallel β-sheets of W-like topology are arranged around a central water-filled tunnel, with the water molecules arranged as a pentagonal dodecahedron. Tachylectin-2 exhibits five virtually identical binding sites, one in each β-sheet. The binding sites are located between adjacent β-sheets and are made by a large loop between the outermost strands of the β-sheets and the connecting segment from the previous β-sheet. The high number of five binding sites within the single polypeptide chain strongly suggests the recognition of carbohydrate surface structures of pathogens with a fairly high ligand density. Thus, tachylectin-2 employs strict specificity for certain N-acetyl sugars as well as the surface ligand density for self/non-self recognition.

本文言語英語
ページ(範囲)2313-2322
ページ数10
ジャーナルEMBO Journal
18
9
DOI
出版ステータス出版済み - 5月 4 1999

!!!All Science Journal Classification (ASJC) codes

  • 神経科学(全般)
  • 分子生物学
  • 生化学、遺伝学、分子生物学(全般)
  • 免疫学および微生物学(全般)

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