Solvent-accessible residues on the metal ion-dependent adhesion site face of integrin CR3 mediate its binding to the neutrophil inhibitory factor
Solvent-accessible residues on the metal ion-dependent adhesion site face of integrin CR3 mediate its binding to the neutrophil inhibitory factor
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DOI：
10.1074/jbc.271.27.15858
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发表时间：
1996-07-05
影响因子：
4.8
通讯作者：
Arnaout, MA
中科院分区：
文献类型：
--
作者：
Rieu, P;Sugimori, T;Arnaout, MA
中性粒细胞粘附依赖的功能，如趋化、扩散和吞噬被中性粒细胞抑制因子（NIF）抑制，中性粒细胞抑制因子是钩虫产生的一种糖蛋白。NIF结合位点定位于整合素CR3 （CD11b/CD18）的a结构域，并被证明是金属依赖的，最近解决的CD11b a结构域的晶体结构揭示了在结构顶部假定的金属离子依赖的粘附位点（MIDAS）。为了确定NIF是否在其MIDAS表面与a结构域结合，在结构的表面环和相邻螺旋中创建了涉及24个残基的氨基酸取代。然后用盲法测试表达的CD11b a -domain和CR3异源二聚体与生物素化的NIF结合的能力。溶剂暴露的Gly（143）、Asp（149）、Glu(178)-Glu（179）和Arg（208）均位于MIDAS表面，靠近金属离子，参与CR3-NIF相互作用。这些数据表明，天然整合素拮抗剂NIF通过MIDAS区域与CR3结合，并在该区域确定可能的靶向治疗接触残基。
Neutrophil adhesion dependent functions such as chemotaxis, spreading, and phagocytosis are inhibited by neutrophil inhibitory factor (NIF), a glycoprotein produced by the hookworm Ancylostoma caninum. The NIF binding site has been localized to the A-domain of integrin CR3 (CD11b/CD18) and shown to be metal-dependent, The recently solved crystal structure of the A-domain from CD11b revealed a putative metal ion-dependent adhesion site (MIDAS) on the top of the structure. To determine if NIF binds to the A-domain at its MIDAS face, amino acid substitutions involving 24 residues present in surface loops and adjacent helices in the structure were created. The expressed CD11b A-domain and CR3 heterodimers were then tested in a blinded manner for their ability to bind to biotinylated NIF. The solvent-exposed Gly(143), Asp(149), Glu(178)-Glu(179), and Arg(208), all located on the MIDAS face, in close proximity to the metal ion, were involved in CR3-NIF interaction. These data show that the natural integrin antagonist, NIF, binds to CR3 through the MIDAS region and identify putative contact residues in this region that could be targeted therapeutically.