Department of Chemistry, University of Zurich, 8006 Zurich, Switzerland.
J Phys Chem Lett. 2021 May 6;12(17):4262-4267. doi: 10.1021/acs.jpclett.1c00915. Epub 2021 Apr 27.
While much is known about different allosteric regulation mechanisms, the nature of the allosteric signal and the time scale on which it propagates remains elusive. The PDZ3 domain from postsynaptic density-95 protein is a small protein domain with a terminal third α-helix, i.e., the α3-helix, which is known to be allosterically active. By cross-linking the allosteric helix with an azobenzene moiety, we obtained a photocontrollable PDZ3 variant. Photoswitching triggers its allosteric transition, resulting in a change in binding affinity of a peptide to the remote binding pocket. Using time-resolved infrared and UV/vis spectroscopy, we follow the allosteric signal transduction and reconstruct the timeline in which the allosteric signal propagates through the protein within 200 ns.
尽管人们对不同的别构调节机制有了很多了解，但别构信号的性质及其传播的时间尺度仍然难以捉摸。突触后密度蛋白 95 的 PDZ3 结构域是一个具有末端第三个α-螺旋的小蛋白结构域，即α3-螺旋，已知其具有别构活性。通过将别构螺旋与偶氮苯部分交联，我们获得了一种光控 PDZ3 变体。光开关触发其别构转变，导致肽与远程结合口袋的结合亲和力发生变化。使用时间分辨红外和紫外/可见光谱，我们跟踪别构信号转导，并在 200 ns 内重建别构信号在蛋白质中传播的时间线。
