Lee Xiao Yin, Van Eynde Wout, Helsen Christine, Willems Hanne, Peperstraete Kaat, De Block Sofie, Voet Arnout, Claessens Frank
Molecular Endocrinology Laboratory, Department of Cellular and Molecular Medicine, Campus Gasthuisberg ON1 Herestraat 49 - box 901, Leuven 3000, Belgium.
Department of Chemistry, Laboratory of Biomolecular Modelling and Design, Heverlee 3001, Belgium.
J Steroid Biochem Mol Biol. 2024 Jul;241:106499. doi: 10.1016/j.jsbmb.2024.106499. Epub 2024 Apr 10.
The androgen receptor (AR) is a steroid activated transcription factor which recognizes DNA motifs resembling inverted repeats of a conserved 5'-AGAACA-3'-like hexanucleotides separated by a three-nucleotide spacer from a similar, but less conserved hexanucleotide. Here, we report the structures of the human AR DNA binding domain (DBD) bound to two natural AREs (C3 and MTV) in head-to-head dimer conformations, diffracting at 2.05 Å and 2.25 Å, respectively. These structures help to explain the impact of androgen insensitivity mutations on the structure integrity, DNA binding and DBD dimerization. The binding affinity of the AR DBD to different DNA motifs were measured by the BioLayer Interferometry (BLI) and further validated by Molecular Dynamics (MD) simulations. This shows that the high binding affinity of the first DBD to the upstream 5'-AGAACA-3' motif induces the cooperative binding of the second DBD to the second hexanucleotide. Our data indicate identical interaction of the DBDs to the upstream hexanucleotides, while forming an induced closer contact of the second DBD on the non-canonical hexanucleotides. The variation in binding between the DBD monomers are the result of differences in DNA occupancy, protein-protein interactions, DNA binding affinity, and DNA binding energy profiles. We propose this has functional consequences.
雄激素受体（AR）是一种类固醇激活的转录因子，它识别的DNA基序类似于由一个三核苷酸间隔隔开的保守的5'-AGAACA-3'-样六核苷酸反向重复序列，该间隔与一个相似但保守性较低的六核苷酸相邻。在此，我们报告了人AR DNA结合结构域（DBD）与两个天然雄激素反应元件（C3和MTV）以头对头二聚体构象结合的结构，其衍射分辨率分别为2.05 Å和2.25 Å。这些结构有助于解释雄激素不敏感突变对结构完整性、DNA结合和DBD二聚化的影响。通过生物层干涉术（BLI）测量了AR DBD对不同DNA基序的结合亲和力，并通过分子动力学（MD）模拟进一步验证。这表明第一个DBD对上游5'-AGAACA-3'基序的高结合亲和力诱导了第二个DBD与第二个六核苷酸的协同结合。我们的数据表明DBD与上游六核苷酸的相互作用相同，同时第二个DBD在非经典六核苷酸上形成诱导的紧密接触。DBD单体之间结合的差异是DNA占据、蛋白质-蛋白质相互作用、DNA结合亲和力和DNA结合能量分布不同的结果。我们认为这具有功能上的影响。
