Tong L, Warren T C, King J, Betageri R, Rose J, Jakes S
Department of Inflammatory Diseases, Boehringer Ingelheim Pharmaceuticals Inc. Ridgefield, CT 06877, USA.
J Mol Biol. 1996 Mar 1;256(3):601-10. doi: 10.1006/jmbi.1996.0112.
src homology 2 (SH2) domains are modules of about 100 amino acid residues and bind to phosphotyrosine-containing motifs in a sequence-specific manner. They play important roles in intracellular signal transduction and represent potential targets for pharmacological intervention. The protein tyrosine kinase p56lck is a member of the src family and is involved in T-cell activation. The crystal structure of its SH2 domain with an 11-residue peptide showed that the phosphotyrosine and the Ile residue at the pY + 3 position are recognized by the SH2 domain. We present here the crystal structure of the SH2 domain of human p56lck in complex with the short phosphotyrosyl peptide Ac-pTyr-Glu-Glu-Ile (pYEEI peptide) at 1.0 A resolution. The structural analysis at atomic resolution reveals that residue Arg134 (alphaA2), which interacts with the phosphotyrosine side-chain, is present in two conformations in the complex. The structure at 1.8 A resolution of the complex with the phosphotyrosyl peptide Ac-pTyr-Glu-Glu-Gly (pYEEG peptide), which is 11 fold less potent, shows another binding mode for the pY + 3 residue as well as rearrangements of the side-chain of Arg196 (EF3) and one of the water molecules at the base of the pY + 3 pocket. The structure of the complex with the short pYEEI peptide at atomic resolution represents a good starting point for the design and optimization of new inhibitors. Comparative structural analysis of many different inhibitor complexes will be an important component of this drug discovery process.
Src同源2（SH2）结构域由约100个氨基酸残基组成，能以序列特异性方式结合含磷酸酪氨酸的基序。它们在细胞内信号转导中发挥重要作用，是药物干预的潜在靶点。蛋白酪氨酸激酶p56lck是Src家族成员，参与T细胞活化。其SH2结构域与一个11残基肽段的晶体结构表明，磷酸酪氨酸和pY + 3位置的异亮氨酸残基被SH2结构域识别。我们在此展示了人p56lck的SH2结构域与短磷酸酪氨酸肽Ac-pTyr-Glu-Glu-Ile（pYEEI肽）复合物在1.0埃分辨率下的晶体结构。原子分辨率的结构分析表明，与磷酸酪氨酸侧链相互作用的精氨酸残基Arg134（αA2）在复合物中存在两种构象。与活性低11倍的磷酸酪氨酸肽Ac-pTyr-Glu-Glu-Gly（pYEEG肽）复合物在1.8埃分辨率下的结构，显示了pY + 3残基的另一种结合模式以及精氨酸残基Arg196（EF3）侧链和pY + 3口袋底部一个水分子的重排。原子分辨率下与短pYEEI肽复合物的结构是设计和优化新型抑制剂的良好起点。对许多不同抑制剂复合物的比较结构分析将是这一药物发现过程的重要组成部分。
