Schmeing Stefan, Amrahova Gulshan, Bigler Katrin, Chang Jen-Yao, Openy Joseph, Pal Sunit, Posada Laura, Gasper Raphael, 't Hart Peter
Chemical Genomics Centre of the Max Planck Society, Max Planck Institute of Molecular Physiology Otto-Hahn-Strasse 11 44227 Dortmund Germany
Crystallography and Biophysics Unit, Max-Planck-Institute of Molecular Physiology Otto-Hahn-Strasse 11 44227 Dortmund Germany.
Chem Sci. 2023 Jul 13;14(31):8269-8278. doi: 10.1039/d3sc00985h. eCollection 2023 Aug 9.
The diverse role of the splicing factor PTBP1 in human cells has been widely studied and was found to be a driver for several diseases. PTBP1 binds RNA through its RNA-recognition motifs which lack obvious pockets for inhibition. A unique transient helix has been described to be part of its first RNA-recognition motif and to be important for RNA binding. In this study, we further confirmed the role of this helix and envisioned its dynamic nature as a unique opportunity to develop stapled peptide inhibitors of PTBP1. The peptides were found to be able to inhibit RNA binding fluorescence polarization assays and directly occupy the helix binding site as observed by protein crystallography. These cell-permeable inhibitors were validated to alter the regulation of alternative splicing events regulated by PTBP1. Our study demonstrates transient secondary structures of a protein can be mimicked by stapled peptides to inhibit allosteric mechanisms.
剪接因子PTBP1在人类细胞中的多样作用已得到广泛研究，并且发现它是多种疾病的驱动因素。PTBP1通过其RNA识别基序结合RNA，这些基序缺乏明显的抑制口袋。一种独特的瞬时螺旋已被描述为其首个RNA识别基序的一部分，并且对RNA结合很重要。在本研究中，我们进一步证实了该螺旋的作用，并设想其动态性质是开发PTBP1的订书肽抑制剂的独特机会。通过荧光偏振测定法发现这些肽能够抑制RNA结合，并且如蛋白质晶体学所观察到的，它们直接占据螺旋结合位点。这些可穿透细胞的抑制剂经过验证可改变由PTBP1调节的可变剪接事件的调控。我们的研究表明，蛋白质的瞬时二级结构可以被订书肽模拟以抑制变构机制。
