Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland.
J Am Soc Mass Spectrom. 2010 Apr;21(4):635-45. doi: 10.1016/j.jasms.2009.12.004. Epub 2009 Dec 28.
Nuclear receptors, such as the retinoic acid receptor (RAR) or the 9-cis retinoic acid receptor (RXR), interact not only with their ligands but also with other types of receptors and with DNA. Here, two complementary mass spectrometry (MS) methods were used to study the interactions between retinoic receptors (RXR/RAR) and DNA: non-denaturing nano-electrospray (nanoESI MS), and high-mass matrix-assisted laser desorption ionization (MALDI MS) combined with chemical cross-linking. The RAR x RXR heterodimer was studied in the presence of a specific DNA sequence (DR5), and a specific RAR x RXR x DNA complex was detected with both MS techniques. RAR by itself showed no significant homodimerization. A complex between RAR and the double stranded DR5 was detected with nanoESI. After cross-linking, high-mass MALDI mass spectra showed that the RAR binds the single stranded DR5, and the RAR dimer binds both single and double stranded DR5. Moreover, the MALDI mass spectrum shows a larger RAR dimer signal in the presence of DNA. These results suggest that a gene-regulatory site on DNA can induce quaternary structural changes in a transcription factor such as RAR.
核受体，如视黄酸受体（RAR）或 9-顺式视黄酸受体（RXR），不仅与它们的配体相互作用，还与其他类型的受体和 DNA 相互作用。在这里，使用两种互补的质谱（MS）方法来研究视黄酸受体（RXR/RAR）与 DNA 的相互作用：非变性纳升电喷雾（nanoESI MS）和高质量基质辅助激光解吸电离（MALDI MS）与化学交联相结合。在特定 DNA 序列（DR5）存在下研究 RAR x RXR 异二聚体，并用两种 MS 技术检测到特定的 RAR x RXR x DNA 复合物。RAR 本身没有明显的同源二聚化。用 nanoESI 检测到 RAR 与双链 DR5 之间的复合物。交联后，高质量 MALDI 质谱显示 RAR 结合单链 DR5，RAR 二聚体结合单链和双链 DR5。此外，MALDI 质谱在存在 DNA 的情况下显示出更大的 RAR 二聚体信号。这些结果表明，DNA 上的基因调节位点可以诱导转录因子（如 RAR）的四级结构变化。
