The specificity of the N-terminal SH2 domain of SHP-2 is modified by a single point mutation
The specificity of the N-terminal SH2 domain of SHP-2 is modified by a single point mutation
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DOI：
10.1021/bi9722913
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发表时间：
1998-03-03
期刊：
影响因子：
2.9
通讯作者：
Ramachandran, C
中科院分区：
文献类型：
--
作者：
Huyer, G;Ramachandran, C
SH2 结构域是类似于 100 个氨基酸的小蛋白结构域，在靶标 pY 周围的特定序列中与磷酸酪氨酸 (pY) 结合。一般来说，结合靶标 pY C 端的残基被认为对于定义结合特异性最重要，特别是 pY + 1 和 pY + 3 残基（即 pY C 端的第一个和第三个氨基酸）。然而，我们之前对蛋白酪氨酸磷酸酶 SHP-2 的 SH2 结构域的研究 [Huyer, G., Li, Z. M., Adam, M., Huckle, W. R., 和 Ramachandran, C. (1995) Biochemistry 34, 1040-1049] 也表明与 pY - 2 残基存在重要的相互作用。在 SHP-2 的 SH2 结构域中，高度保守的 α A2 Arg 被 Gly 取代。已发表的 Src SH2 结构域和与高亲和力肽复合的 SHP-2 N 端 SH2 结构域的晶体结构的比较表明，SHP-2 的 α A2 Gly 产生了一个间隙，该间隙由结合肽的 pY - 2 残基的侧链填充。据预测，用精氨酸取代该甘氨酸将改变或消除 pY - 2 残基参与结合。构建了 alpha A2 Gly --> Arg 突变体，事实上，该突变体不再需要目标 pY 的 N 端残基来进行高亲和力结合，使其特异性更像其他 SH2 结构域。 α A2 Gly 显然参与指导该 SH2 结构域的结合序列中 pY - 2 残基的不寻常需求，这对其体内靶向和特异性具有重要意义。
SH2 domains are small protein domains of similar to 100 amino acids that bind to phosphotyrosine (pY) in the context of a specific sequence surrounding the target pY. In general, the residues C-terminal to the pY of the binding target are considered most important for defining the binding specificity, and in particular the pY + 1 and pY + 3 residues (i.e., the first and third amino acids C-terminal to the pY). However, our previous studies with the SH2 domains of the protein tyrosine phosphatase SHP-2 [Huyer, G., Li, Z. M., Adam, M., Huckle, W. R., and Ramachandran, C. (1995) Biochemistry 34, 1040-1049] indicated important interactions with the pY - 2 residue as well. In the SH2 domains of SHP-2, the highly conserved alpha A2 Arg is replaced by Gly. A comparison of the published crystal structures of the Src SH2 domain and the N-terminal SH2 domain of SHP-2 complexed with high-affinity peptides suggested that the alpha A2 Gly of SHP-2 creates a gap which is filled by the side chain of the pY - 2 residue of the bound peptide. It was predicted that replacing this Gly with Arg would alter or eliminate the involvement of the pY - 2 residue in binding. The alpha A2 Gly --> Arg mutant was constructed, and indeed, this mutant no longer required residues N-terminal to the target pY for high-affinity binding, making its specificity more like that of other SH2 domains. The alpha A2 Gly is clearly involved in directing the unusual requirement for the pY - 2 residue in the binding sequence of this SH2 domain, which has important implications for its in vivo targeting and specificity.