Department of Medicinal Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark.
Proc Natl Acad Sci U S A. 2012 Feb 28;109(9):3317-22. doi: 10.1073/pnas.1113761109. Epub 2012 Feb 17.
Inhibition of the ternary protein complex of the synaptic scaffolding protein postsynaptic density protein-95 (PSD-95), neuronal nitric oxide synthase (nNOS), and the N-methyl-D-aspartate (NMDA) receptor is a potential strategy for treating ischemic brain damage, but high-affinity inhibitors are lacking. Here we report the design and synthesis of a novel dimeric inhibitor, Tat-NPEG4(IETDV)(2) (Tat-N-dimer), which binds the tandem PDZ1-2 domain of PSD-95 with an unprecedented high affinity of 4.6 nM, and displays extensive protease-resistance as evaluated in vitro by stability-measurements in human blood plasma. X-ray crystallography, NMR, and small-angle X-ray scattering (SAXS) deduced a true bivalent interaction between dimeric inhibitor and PDZ1-2, and also provided a dynamic model of the conformational changes of PDZ1-2 induced by the dimeric inhibitor. A single intravenous injection of Tat-N-dimer (3 nmol/g) to mice subjected to focal cerebral ischemia reduces infarct volume with 40% and restores motor functions. Thus, Tat-N-dimer is a highly efficacious neuroprotective agent with therapeutic potential in stroke.
三元蛋白质复合物的抑制突触支架蛋白后突触密度蛋白-95（PSD-95）、神经元型一氧化氮合酶（nNOS）和 N-甲基-D-天冬氨酸（NMDA）受体是治疗缺血性脑损伤的一种潜在策略，但缺乏高亲和力的抑制剂。在这里，我们报告了一种新型二聚体抑制剂 Tat-NPEG4(IETDV)(2)（Tat-N-二聚体）的设计和合成，它与 PSD-95 的串联 PDZ1-2 结构域具有前所未有的高亲和力（4.6 nM），并且在体外通过人血浆中的稳定性测量评估显示出广泛的蛋白酶抗性。X 射线晶体学、NMR 和小角 X 射线散射（SAXS）推断出二聚体抑制剂与 PDZ1-2 之间存在真正的二价相互作用，并提供了 PDZ1-2 构象变化的动态模型，由二聚体抑制剂诱导。单次静脉注射 3 nmol/g 的 Tat-N-二聚体（3 nmol/g）可使局灶性脑缺血小鼠的梗死体积减少 40%，并恢复运动功能。因此，Tat-N-二聚体是一种高效的神经保护剂，具有治疗中风的潜力。
