Retinoic Acid Receptors: Dynamics, Stability and Folding

描述（由申请人提供）：类视黄酸受体（RXR）与视黄酸受体（RAR）或其他核激素受体作为同二聚体或异二聚体调节基因表达。受类维甲酸调节的基因包括介导细胞凋亡、胆固醇吸收和外排、外源代谢酶的表达和致癌基因v- erba。由于RXR和RAR在生长、发育和细胞分化中发挥的重要作用，类维甲酸作为化学预防和化学治疗药物备受关注。它们也用于治疗痤疮、牛皮癣和癌前病变。虽然已经确定了几种类维生素a受体的x射线结构，但关于这些蛋白质的动力学和稳定性以及配体对这些特性的影响的信息还缺乏。本研究将使用质谱法结合氢/氘交换来(1)研究RARgamma和RXRalpha配体结合域的动力学，以及配体和蛋白质的季元结构对结构元素在溶剂中的可及性的影响；(2)探索这些蛋白质折叠的动力学机制；(3)分析不同蛋白酶敏感性的构象变化。还提出了热力学和动力学研究来研究折叠的能量学和机制。这些研究提供了补充静态结构数据的信息，为未来的工作奠定了基础，以表征这些蛋白质与其信号转导途径的其他成分的相互作用，并提供了新的数据，可能有助于设计更有效的药物，作用于类维生素a受体。

DESCRIPTION (provided by applicant): Retinoid X receptors (RXR) act as homodimers or heterodimers with retinoic acid receptors (RAR) or other nuclear hormone receptors to regulate gene expression. Among the genes regulated by retinoids are those that mediate apoptosis, cholesterol absorption and efflux, expression of xenobiotic metabolizing enzymes and the oncogene v-Erb A. Because of the important roles that RXR and RAR play in growth, development and cellular differentiation retinoids are of interest as chemopreventative and chemotherapeutic agents. They are also used in the treatment of acne, psoriasis and precancerous lesions. Although X-ray structures of several receptors for retinoids have been determined, information concerning the dynamics and stability of these proteins and the effects of ligands on these properties is lacking. This proposal will use mass spectrometry in conjunction with hydrogen/deuterium exchange to (1) examine the dynamics of the RARgamma and RXRalpha ligand binding domains and the effects of ligands and protein quaternary structure on solvent accessibility of structural elements, (2) probe the kinetic mechanism by which these proteins fold and (3) analyze conformational changes by differential protease sensitivity. Thermodynamic and kinetic studies are also proposed to examine the energetics and mechanisms of folding. These studies give information that complements the static, structural data, forms the foundation for future work to characterize the interactions of these proteins with other components of their signal transduction pathways and provides new data that may aid in the design of more effective drugs that act on receptors for retinoids.