Targeted mutation of key residues at the start of helix 12 in the hERalpha ligand-binding domain identifies the role of hydrogen-bonding and hydrophobic interactions in the activity of the protein.
Targeted mutation of key residues at the start of helix 12 in the hERalpha ligand-binding domain identifies the role of hydrogen-bonding and hydrophobic interactions in the activity of the protein.
复制标题
hERα 配体结合结构域中螺旋 12 起始处的关键残基的靶向突变确定了氢键和疏水相互作用在蛋白质活性中的作用。
DOI：
10.1016/j.jsbmb.2005.06.036
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Skafar,DebraF
中科院分区：
文献类型：
--
作者：
Zhao,Changqing;Abrams,Judith;Skafar,DebraF
雌激素（E2）和他莫昔芬通过核受体超家族的两个成员雌激素受体（ER）-α和-β发挥作用。我们希望确定连接配体结合和ERα活性的关键相互作用。Asp-351和Leu-536参与ERα配体结合结构域（LBD）螺旋12起始处的氢键（Asp-351）和疏水（Leu-536）相互作用。每个位置的突变都会改变ER活性，但我们不知道哪个更重要。我们对这些残基进行了组合和单独突变，并评估了在ERE驱动和AP-1驱动启动子上存在和不存在E2和4-OHT的情况下突变ER的活性，以及它们与辅调节因子相互作用的能力。在ER驱动的启动子上，351位的残基决定了E2是否刺激或降低ER的活性，以及在4-OHT存在下的活性水平。令人惊讶的是，两个残基的突变通常不产生累积的有害影响，并且它们对两个启动子上的基础活性产生平衡作用。我们的研究结果确定了特定的相互作用对hERα活性的贡献，并支持该区域将配体结合与ER活性偶联的概念。
Estradiol (E2) and tamoxifen exert their effects through two members of the nuclear receptor superfamily, estrogen receptor (ER)-alpha and -beta. We want to identify the key interactions linking ligand-binding and activity of the ERα. Asp-351 and Leu-536 participate in hydrogen bond (Asp-351) and hydrophobic (Leu-536) interactions at the start of helix 12 in the ligand-binding domain (LBD) of the ERα. Mutations at each position alter ER activity, but we do not know which is more important. We mutated these residues in combination and individually and assessed the activity of the mutated ERs in the absence and presence of E2and 4-OHT on an ERE-driven and an AP-1-driven promoter, as well as their ability to interact with coregulators. On an ERE-driven promoter, the residue at position 351 determined whether E2stimulated or reduced the activity of the ER, as well as the level of activity in the presence of 4-OHT. Surprisingly, mutation of both residues generally did not produce cumulative deleterious effects, and they exerted counterbalancing effects on the basal activity on both promoters. Our results identify the contributions of specific interactions to the activity of the hERα, and support the concept that this region couples ligand-binding with ER activity.