Equipe Oncoprotéines, Ecole Supérieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, 67412 Illkirch Cedex, France.
J Mol Biol. 2011 Mar 11;406(5):745-63. doi: 10.1016/j.jmb.2011.01.015. Epub 2011 Jan 13.
PDZ domains are protein interaction domains that are found in cytoplasmic proteins involved in signaling pathways and subcellular transport. Their roles in the control of cell growth, cell polarity, and cell adhesion in response to cell contact render this family of proteins targets during the development of cancer. Targeting of these network hubs by the oncoprotein E6 of "high-risk" human papillomaviruses (HPVs) serves to effect the efficient disruption of cellular processes. Using NMR, we have solved the three-dimensional solution structure of an extended construct of the second PDZ domain of MAGI-1 (MAGI-1 PDZ1) alone and bound to a peptide derived from the C-terminus of HPV16 E6, and we have characterized the changes in backbone dynamics and hydrogen bonding that occur upon binding. The binding event induces quenching of high-frequency motions in the C-terminal tail of the PDZ domain, which contacts the peptide upstream of the canonical X-[T/S]-X-[L/V] binding motif. Mutations designed in the C-terminal flanking region of the PDZ domain resulted in a significant decrease in binding affinity for E6 peptides. This detailed analysis supports the notion of a global response of the PDZ domain to the binding event, with effects propagated to distal sites, and reveals unexpected roles for the sequences flanking the canonical PDZ domain boundaries.
PDZ 结构域是存在于参与信号通路和细胞内运输的细胞质蛋白中的蛋白质相互作用结构域。它们在控制细胞生长、细胞极性和细胞黏附中的作用，使得这个蛋白家族成为癌症发展过程中的靶点。致癌蛋白 E6 可靶向这些网络枢纽，从而有效地破坏细胞过程。我们使用 NMR 技术，分别解决了 MAGI-1（MAGI-1 PDZ1）第二个 PDZ 结构域的扩展构建体以及与 HPV16 E6 C 末端衍生肽结合的三维溶液结构，并对结合过程中发生的骨架动力学和氢键变化进行了表征。结合事件诱导 PDZ 结构域 C 端尾部高频运动的猝灭，该尾部与经典 X-[T/S]-X-[L/V]结合基序上游的肽接触。在 PDZ 结构域的 C 端侧翼区域设计的突变导致与 E6 肽的结合亲和力显著降低。这种详细的分析支持 PDZ 结构域对结合事件的整体反应的概念，其影响传播到远端位点，并揭示了经典 PDZ 结构域边界侧翼序列的意外作用。
