Chio Cynthia M, Cheng Karen W, Bishop Anthony C
Department of Chemistry, Amherst College, Amherst, MA 01002 (USA).
Chembiochem. 2015 Aug 17;16(12):1735-9. doi: 10.1002/cbic.201500245. Epub 2015 Jun 30.
Few chemical strategies for activating enzymes have been developed. Here we show that a biarsenical compound (FlAsH) can directly activate a rationally engineered protein tyrosine phosphatase (Shp2 PTP) by disrupting autoinhibitory interactions between Shp2's N-terminal SH2 domain and its PTP domain. We found that introducing a tricysteine motif at a loop of Shp2's N-SH2 domain confers affinity for FlAsH; binding of FlAsH to the cysteine-enriched loop relieves Shp2's inhibitory interdomain interaction and substantially increases the enzyme's PTP activity. Activation of engineered Shp2 is substrate independent and is observed in the contexts of both purified enzyme and complex proteomes. A chemical means for activating Shp2 could be useful for investigating its roles in signaling and oncogenesis, and the loop-targeting strategy described herein could provide a blueprint for the development of target-specific activators of other autoinhibited enzymes.
目前已开发出的用于激活酶的化学策略很少。在此我们表明，一种双砷化合物（FlAsH）可以通过破坏Shp2的N端SH2结构域与其PTP结构域之间的自抑制相互作用，直接激活一种经过合理设计的蛋白酪氨酸磷酸酶（Shp2 PTP）。我们发现，在Shp2的N-SH2结构域的一个环处引入一个三半胱氨酸基序可赋予对FlAsH的亲和力；FlAsH与富含半胱氨酸的环的结合可缓解Shp2的抑制性结构域间相互作用，并显著提高该酶的PTP活性。工程化Shp2 的激活不依赖于底物，在纯化酶和复杂蛋白质组的情况下均能观察到。激活Shp2的化学方法可能有助于研究其在信号传导和肿瘤发生中的作用，本文所述的环靶向策略可为开发其他自抑制酶的靶点特异性激活剂提供蓝图。
