STRUCTURE OF P-GLYCOPROTEIN BY ELECTRON MICROSCOPY

电子显微镜下 P-糖蛋白的结构

• 批准号: 7092555
• 负责人: Stephan Wilkens
• 金额: $ 17.03万
• 依托单位: UPSTATE MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7092555
• 关键词: P glycoprotein; X ray crystallography; adenosine triphosphate; binding sites; biological transport; computer simulation; electron microscopy; glycoprotein structure; hydrolysis; lipid bilayer membrane; multidrug resistance; structural biology

DESCRIPTION (provided by applicant): P-glycoprotein (Pgp; also called multidrug resistance protein) is found in the plasma membrane of higher eukaryotes where it is responsible for ATP-hydrolysis-driven export of hydrophobic molecules. In animals, Pgp plays an important role in excretion of and protection from environmental toxins. When expressed in the plasma membrane of human cancer cells, Pgp can lead to failure of chemotherapy by preventing the hydrophobic chemotherapeutic drugs from reaching their targets inside the cells. Pgp is a member of the superfamily of ATP binding cassette (ABC) transporter proteins. ABC transporters consist typically of four domains, two nucleotide binding domains (NBDs) located in the cytoplasm and two trans-membrane domains (TMDs) responsible for drug binding and transport. Despite its important role in human disease, relatively little is known about the structure of Pgp. We are using electron microscopy of two-dimensional crystals to study the structure of Pgp. The immediate goals of this proposal are 1) to visualize the structural changes Pgp is undergoing during the catalytic cycle, 2) to calculate a three dimensional model of Pgp trapped at the different steps during ATP hydrolysis and drug transport and 3) to optimize the conditions under which we currently generate two dimensional crystals of Pgp. The structural studies will be conducted with Pgp crystallized in its native environment, the lipid bilayer. A three dimensional model of Pgp will serve as a basis for resolving the structural changes which Pgp is expected to undergo during the drug transport cycle. Understanding these structural changes might ultimately aid in the design for specific inhibitors for the protein in order to be able to regulate the activity of Pgp for a more effective chemotherapy.

描述（由申请人提供）：P-糖蛋白（Pgp；也称为多药耐药蛋白）存在于高等真核生物的质膜中，负责 ATP 水解驱动的疏水性分子的输出。在动物中，Pgp 在排泄和保护环境毒素方面发挥着重要作用。当 Pgp 在人类癌细胞的质膜中表达时，它会阻止疏水性化疗药物到达细胞内的靶标，从而导致化疗失败。 Pgp 是 ATP 结合盒 (ABC) 转运蛋白超家族的成员。 ABC 转运蛋白通常由四个结构域组成，两个位于细胞质的核苷酸结合结构域 (NBD) 和两个负责药物结合和转运的跨膜结构域 (TMD)。尽管 Pgp 在人类疾病中发挥着重要作用，但人们对 Pgp 的结构知之甚少。我们正在使用二维晶体的电子显微镜来研究 Pgp 的结构。该提案的直接目标是 1) 可视化 Pgp 在催化循环期间经历的结构变化，2) 计算 ATP 水解和药物转运过程中不同步骤中捕获的 Pgp 的三维模型，3) 优化我们目前生成 Pgp 二维晶体的条件。结构研究将使用在其天然环境（脂双层）中结晶的 Pgp 进行。 Pgp 的三维模型将作为解决 Pgp 在药物转运周期中预期发生的结构变化的基础。了解这些结构变化可能最终有助于设计该蛋白质的特定抑制剂，以便能够调节 Pgp 的活性，从而实现更有效的化疗。