蛋白质相互作用界面中磷酸酪氨酸质子化状态的判定研究

Determination Study of the Protonation State of the Phosphotyrosine in the Protein Interaction Interface

蛋白质相互作用界面上磷酸酪氨酸的质子化状态对蛋白质相互作用具有重要影响,在进行相关结构的计算研究时,必须对其进行准确判定.采用AMBER/parm99力场和广义波恩(GBobc)隐式水模型,以SHC1(src homology2domain-containing transforming proteinC1)的SH2(Src homology2)结构域与磷酸化激活的T细胞受体CD247链的相互作用核磁结构为例,首次以热力学积分方法对相互作用界面上磷酸酪氨酸的质子化状态进行判定研究,结果显示该方法计算精确,判定结果与实验结果一致.表明该方法不仅为涉及磷酸酪氨酸的蛋白质相互作用的计算结构研究奠定了基础,在其它具有可电离基团的氨基酸的质子化状态判定中也将具有潜在的推广应用价值.

The protonation state of phosphotyrosine in protein interaction interface has an important impact on protein interactions, and thus should be determined correctly before computational study. Using the NMR structure of the SH2 domain of SHC1 bound with a phosphorylated CD247 chain of T cell receptor as an example, the protonation state of phosphotyrosine was studied by thermodynamic integration with AMBER/parm99 force field and GB^obe implicit water model for the first time. The result showed that the computation was accurate, and the protonation state determined by this computation was in accordance with the experimental result. This study suggests that this method not only make a sound foundation for the future computational structural studies with phosphotyrosines involved, but also have potential application to the protonation state determinations of other amino acids with titratable groups.