Ligand-Driven Vectorial Folding of Ribosome-Bound Human CFTR NBD1
Ligand-Driven Vectorial Folding of Ribosome-Bound Human CFTR NBD1
复制标题
DOI：
10.1016/j.molcel.2011.02.027
复制
发表时间：
2011-03-18
期刊：
影响因子：
16
通讯作者：
Skach, William R.
中科院分区：
文献类型：
--
作者：
Khushoo, Amardeep;Yang, Zhongying;Skach, William R.
蛋白质折叠与生物合成耦合的机制是蛋白质构象疾病的一个关键但人们知之甚少的方面。在这里，我们使用荧光共振能量转移（FRET）来表征新生多肽的三级结构转变，并表明人类CFTR的第一个核苷酸结合域（NBD1）在囊性纤维化中折叠有缺陷，在核糖体上合成时通过共翻译多步途径折叠。当 NBD1 残基 389-500 从核糖体出口隧道中出现时，折叠突然开始，启动一个小的 N 末端 α/β 子结构域的压缩。同步新生链的实时动力学表明，子结构域折叠速度很快，与合成同时发生，并且通过 ATP 与新生多肽的直接结合来促进。这些发现将主要的 CF 缺陷定位在 NBD1 折叠途径的后期，并建立了一个范式，其中细胞配体通过促进能量上有利的局部肽构象来促进矢量结构域折叠。
The mechanism by which protein folding is coupled to biosynthesis is a critical, but poorly understood, aspect of protein conformational diseases. Here we use fluorescence resonance energy transfer (FRET) to characterize tertiary structural transitions of nascent polypeptides and show that the first nucleotide-binding domain (NBD1) of human CFTR, whose folding is defective in cystic fibrosis, folds via a co-translational multistep pathway as it is synthesized on the ribosome. Folding begins abruptly as NBD1 residues 389-500 emerge from the ribosome exit tunnel, initiating compaction of a small, N-terminal alpha/beta-subdomain. Real-time kinetics of synchronized nascent chains revealed that subdomain folding is rapid, occurs coincident with synthesis, and is facilitated by direct ATP binding to the nascent polypeptide. These findings localize the major CF defect late in the NBD1 folding pathway and establish a paradigm wherein a cellular ligand promotes vectorial domain folding by facilitating an energetically favored local peptide conformation.