ICAM-2の結晶構造は,特徴的なインテグリン認識表面を明らかにしています
J M Casasnovas1, T A Springer, J H Liu
1The Center for Blood Research, Harvard Medical School, Department of Pathology, Boston, Massachusetts 02115, USA.
Nature
|May 15, 1997
まとめ
細胞間粘着分子-2 (ICAM-2) の結晶構造は,インテグリンがインテグリンとインテグリンなしでどのように作用するかの重要な違いを明らかにしています.
科学分野:
- 細胞の粘着は,細胞の粘着です.
- 構造生物学 構造生物学とは
- 免疫学 免疫学とは
背景:
- インテグリンタンパク質は,細胞-細胞および細胞-細胞外マトリックス相互作用を媒介する.
- 既知のインテグリンリンガンド構造 (フィブロネクチン,VCAM-1) は",I"ドメインが欠けているインテグリンを含む.
- 細胞間粘着分子 (ICAM) は,リンパ球機能関連抗原1 (LFA-1) のような"I"ドメインを含むインテグリンによって認識されます.
研究 の 目的:
- ICAM-2の細胞外領域の結晶構造を決定する.
- ICAM-2のLFA-1認識の構造的基礎を明らかにする.
- 認識サイトアーキテクチャの"I"ドメインを含むと"I"ドメインのないインテグリン-リガンドの相互作用を比較する.
主な方法:
- ICAM-2の3次元構造を決定するためのX線結晶学.
- LFA-1結合に関与する主要な残留物および特徴を特定するための構造分析.
- ICAM-2構造に基づくICAM-1の比較構造モデリング.
主要な成果:
- ICAM-2の細胞外領域の結晶構造が決定されました.
- ICAM-2の位置37 (Glu 37) にあるグルタミン酸は,LFA-1結合に不可欠であり,LFA-1"I"ドメインのMg2+イオンを調整する可能性があります.
- ICAM-2は,ベータストランドにGlu 37を搭載した比較的平らな認識表面を示しており,これはフィブロネクチンとVCAM-1の突起のループと対照的です.
結論:
- "I"ドメインのインテグリンとインテグリンのないインテグリンの間には,認識サイトの構造的な違いが存在します.
- ICAM-2ドメインとN-リンクされたグリカン間の曲がりは,LFA-1結合を促進する可能性があります.
- ICAM-2構造は,ICAM-1認識と潜在的な病原体相互作用を理解するためのモデルを提供します.
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