Conformational change upon ligand binding and dynamics of the PDZ domain from leukemia‐associated Rho guanine nucleotide exchange factor
Conformational change upon ligand binding and dynamics of the PDZ domain from leukemia‐associated Rho guanine nucleotide exchange factor
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DOI：
10.1110/ps.073416508
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发表时间：
2008-06
期刊：
影响因子：
8
通讯作者：
Jiangxin Liu;Jiahai Zhang;Yinshan Yang;Hongda Huang;Weiqun Shen;Q. Hu;Xingsheng Wang;Jihui Wu;Yunyu Shi
中科院分区：
文献类型：
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作者：
Jiangxin Liu;Jiahai Zhang;Yinshan Yang;Hongda Huang;Weiqun Shen;Q. Hu;Xingsheng Wang;Jihui Wu;Yunyu Shi
白血病相关Rho鸟嘌呤核苷酸交换因子（LARG）是一种RhoA特异性鸟嘌呤核苷酸交换因子（GEF），可以激活RhoA。LARG的PDZ （PSD‐95/Disc‐large/ZO‐1同源）结构域与膜受体相互作用，将细胞外信号传递到RhoA信号转导通路。到目前为止，还没有关于这些相互作用的结构和动态信息。在这里，我们报道了LARG PDZ的载脂蛋白形式和与丛蛋白B1 C末端八肽配合物的核磁共振结构。复合物状态下，载子状态下的βB/βC和βE/αB环上的残基出现了不可观测的共振。与其他PDZ相比，LARG PDZ中结合槽的一个明显区域发生了构象变化。利用简化谱密度映射对15N弛豫数据进行分析表明，载子LARG PDZ（特别是其配体结合槽）具有柔性，并在皮秒到纳秒和微秒到毫秒的时间尺度上表现出内部运动。诱变和热力学研究表明，βB/βC和βE/αB环的构象影响pdz -肽的相互作用。这表明构象柔韧性可以促进配体结合时结构的变化。
Leukemia‐associated Rho guanine nucleotide exchange factor (LARG) is a RhoA‐specific guanine nucleotide exchange factor (GEF) that can activate RhoA. The PDZ (PSD‐95/Disc‐large/ZO‐1 homology) domain of LARG interacts with membrane receptors, which can relay extracellular signals to RhoA signal transduction pathways. Until now there is no structural and dynamic information about these interactions. Here we report the NMR structures of the LARG PDZ in the apo form and in complex with the plexin‐B1 C‐terminal octapeptide. Unobservable resonances of the residues in βB/βC and βE/αB loops in apo state were observed in the complex state. A distinct region of the binding groove in the LARG PDZ was found to undergo conformational change compared with other PDZs. Analysis of the 15N relaxation data using reduced spectral density mapping shows that the apo LARG PDZ (especially its ligand‐binding groove) is flexible and exhibits internal motions on both picosecond to nanosecond and microsecond to millisecond timescales. Mutagenesis and thermodynamic studies indicate that the conformation of the βB/βC and βE/αB loops affects the PDZ–peptide interaction. It is suggested that the conformational flexibility could facilitate the change of structures upon ligand binding.