Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
Biochemistry. 2010 Feb 2;49(4):687-95. doi: 10.1021/bi901313x.
All type I interferons (IFNs) bind to a common cell-surface receptor consisting of two subunits. IFNs initiate intracellular signal transduction cascades by simultaneous interaction with the extracellular domains of its receptor subunits, IFNAR1 and IFNAR2. In this study, we mapped the surface of IFNalpha2 interacting with the extracellular domain of IFNAR1 (IFNAR1-EC) by following changes in or the disappearance of the (1)H-(15)N TROSY-HSQC cross peaks of IFNalpha2 caused by the binding of the extracellular domain of IFNAR1 (IFNAR1-EC) to the binary complex of IFNalpha2 with IFNAR2-EC. The NMR study of the 89 kDa complex was conducted at pH 8 and 308 K using an 800 MHz spectrometer. IFNAR1 binding affected a total of 47 of 165 IFNalpha2 residues contained in two large patches on the face of the protein opposing the binding site for IFNAR2 and in a third patch located on the face containing the IFNAR2 binding site. The first two patches form the IFNAR1 binding site, and one of these matches the IFNAR1 binding site previously identified by site-directed mutagenesis. The third patch partially matches the IFNalpha2 binding site for IFNAR2-EC, indicating allosteric communication between the binding sites for the two receptor subunits.
所有的 I 型干扰素（IFNs）都与由两个亚基组成的共同细胞表面受体结合。IFNs 通过与受体亚基 IFNAR1 和 IFNAR2 的细胞外结构域同时相互作用，启动细胞内信号转导级联反应。在这项研究中，我们通过观察（1）H-（15）N TROSY-HSQC 交叉峰的变化或消失，来确定 IFNalpha2 与 IFNAR1 的细胞外结构域（IFNAR1-EC）相互作用的表面位置，这些交叉峰会因 IFNAR1-EC 与 IFNAR2-EC 的二元复合物结合而发生变化。在 pH 8 和 308 K 的条件下，使用 800 MHz 光谱仪对 89 kDa 复合物进行了 NMR 研究。IFNAR1 结合总共影响了 IFNalpha2 中 165 个残基中的 47 个，这些残基位于与 IFNAR2 结合位点相对的蛋白质表面的两个大斑块中，以及位于包含 IFNAR2 结合位点的第三个斑块中。前两个斑块形成了 IFNAR1 结合位点，其中一个与先前通过定点突变鉴定的 IFNAR1 结合位点相匹配。第三个斑块部分与 IFNAR2-EC 的 IFNalpha2 结合位点匹配，表明两个受体亚基的结合位点之间存在变构通讯。
