SH2 DOMAINS EXHIBIT HIGH-AFFINITY BINDING TO TYROSINE-PHOSPHORYLATED PEPTIDES YET ALSO EXHIBIT RAPID DISSOCIATION AND EXCHANGE
SH2 DOMAINS EXHIBIT HIGH-AFFINITY BINDING TO TYROSINE-PHOSPHORYLATED PEPTIDES YET ALSO EXHIBIT RAPID DISSOCIATION AND EXCHANGE
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DOI：
10.1128/mcb.13.3.1449
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发表时间：
1993-03-01
影响因子：
5.3
通讯作者：
SCHLESSINGER, J
中科院分区：
文献类型：
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作者：
FELDER, S;ZHOU, M;SCHLESSINGER, J
细胞内信号分子如磷脂酶C-γ和磷脂酰肌醇3‘-激酶相关蛋白P85的SRC同源2(SH2)结构域代表了激活的生长因子受体上特定的含磷酸酪氨酸区域的识别基序。SH2结构域与激活的生长因子受体结合，控制与信号分子的相互作用及其活性的调节。在这份报告中，我们用实时生物特异性相互作用分析(Biacore)描述了P85的SH2结构域与含有YMXM氨基酸序列基序的短肽的动力学参数和结合亲和力。YMXM来自主要的胰岛素受体底物IRS-1。磷酸肽与P85中包含的两个独立的SH2结构域之间的结合是特异的，并且具有非常高的亲和力，解离常数为0.3到3 nM。非磷酸化的多肽没有可测量的结合，并且相互作用是与磷酸酪氨酸残基非常接近的初级序列所特有的。此外，磷酸肽与其他信号分子的SH2结构域之间的相互作用亲和力要低得多。有趣的是，SH2结构域与酪氨酸磷酸化肽的结合具有很高的亲和力，其开启速率为3×10(7)到40×10(7)/M/S；同时，解离速度很快，为0.11到0.19/S，允许结合蛋白与酪氨酸磷酸化位点的快速交换。
src homology 2 (SH2) domains of intracellular signaling molecules such as phospholipase C-gamma and phosphatidylinositol 3'-kinase-associated protein p85 represent recognition motifs for specific phosphotyrosine-containing regions on activated growth factor receptors. The binding of SH2 domains to activated growth factor receptors controls the interaction with signaling molecules and the regulation of their activities. In this report, we describe the kinetic parameters and binding affinities of SH2 domains of p85 toward short phosphotyrosine-containing peptides with the amino acid sequence motif YMXM, derived from a major insulin receptor substrate, IRS-1, by using real time biospecific interaction analysis (BIAcore). Associations were specific and of very high affinity, with dissociation constants of 0.3 to 3 nM, between phosphopeptides and the two separate SH2 domains contained within p85. Nonphosphorylated peptides showed no measurable binding, and the interactions were specific for the primary sequence very close to the phosphotyrosine residue. Moreover, the interactions between phosphopeptides and SH2 domains of other signaling molecules were of much lower affinity. Interestingly, the binding of the SH2 domains to the tyrosine-phosphorylated peptides was of high affinity as a result of a very high on rate, of 3 x 10(7) to 40 x 10(7)/M/s; at the same time, the rate of dissociation, of 0.11 to 0.19/s, was rapid, allowing for rapid exchange of associating proteins with the tyrosine phosphorylation sites.