Structural Biology of the Apical Bile Acid Transporter

顶端胆汁酸转运蛋白的结构生物学

• 批准号: 7197273
• 负责人: PETER W SWAAN
• 金额: $ 23.16万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2008-09-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7197273
• 关键词: ASBT protein; Address; Affinity; Amino Acids; Apical; Arts; Baculoviruses; Bile Acids; Binding; Cardiovascular Diseases; Carrier Proteins; Cell physiology; Cholesterol Homeostasis; Class; Computational Biology; Computational Molecular Biology; Computer Assisted; Crystallization; Data; Development; Drug Interactions; Drug Kinetics; Drug toxicity; Excretory function; Exhibits; Family member; Future; Genetic; Goals; Homeostasis; Homology Modeling; In Vitro; Individual; Integral Membrane Protein; Intestines; Knowledge; Label; Ligand Binding; Ligand Binding Domain; Ligands; Literature; Mammalian Cell; Mass Spectrum Analysis; Membrane; Membrane Proteins; Methods; Modeling; Molecular; Molecular Target; Movement; Mutagenesis; Numbers; Nutrient; Personal Satisfaction; Pharmaceutical Preparations; Pharmacodynamics; Photoaffinity Labels; Phylogenetic Analysis; Play; Point Mutation; Protein Family; Proteins; Quantitative Structure-Activity Relationship; Recycling; Research; Resolution; Roentgen Rays; Role; Sampling; Scanning; Series; Simulate; Site; Site-Directed Mutagenesis; Sodium; Structure; System; Techniques; Testing; Therapeutic; Transmembrane Domain; Work; absorption; base; bile acid transporter; bile salts; drug testing; hydropathy; hypercholesterolemia; member; molecular modeling; novel strategies; predictive modeling; protein aminoacid sequence; proteoliposomes; reconstitution; solute; structural biology; therapeutic target; three dimensional structure; three-dimensional modeling; uptake

DESCRIPTION (provided by applicant): The apical sodium-dependent bile acid transporter (ASBT) plays a key role in the enterohepatic recycling of bile salts, cholesterol homeostasis, and serves as a molecular target for hypercholesterolemic agents. Although the transporter sequence is known, there is controversy about its membrane topology and very little is known about ASBT structure-function and ligand binding domains. The proposed research will focus on the structural biology of ASBT. Using a novel approach that combines molecular and computational biology our long-term goal is to delineate the three-dimensional structure, ligand-binding domains, and cellular transport mechanism of ASBT. The following specific aims will be addressed: (1) define the membrane topology of ASBT using a series of topology scanning approaches; (2) Construct a comprehensive structural and predictive model of ASBT that can correlate structural point mutations to changes in ligand affinity and transport; (3) Define the functional regions of ASBT by site-directed mutagenesis; we have developed a computer-assisted site-directed mutagenesis approach to probe ASBT protein for amino acid residues implicated in ligand and sodium interactions; (4) Determine the ligand binding domains of ASBT by mass spectrometry; we will employ selective photoaffinity labels to determine ligand-binding peptide sequences. Information gained by these studies will significantly increase our understanding of the structural interactions that drive bile acid transport and further our structural knowledge of solute carrier proteins in general. Additionally, it may aid future development of specific therapeutic strategies against hypercholesterolemia and related cardiovascular diseases.

描述（由申请方提供）：顶端钠依赖性胆汁酸转运蛋白（ASBT）在胆盐的肝肠再循环、胆固醇稳态中发挥关键作用，并作为高胆固醇血症药物的分子靶点。虽然转运蛋白序列是已知的，但关于其膜拓扑结构存在争议，关于ASBT结构-功能和配体结合结构域知之甚少。拟议的研究将集中在ASBT的结构生物学。使用一种新的方法，结合分子和计算生物学，我们的长期目标是描绘的三维结构，配体结合域，和细胞运输机制的ASBT。本论文的主要目的是：（1）通过一系列的拓扑扫描方法确定ASBT的膜拓扑结构;（2）建立一个全面的ASBT结构和预测模型，将结构点突变与配体亲和力和转运的变化联系起来;（3）通过定点突变确定ASBT的功能区域;我们已经开发了一种计算机辅助定点突变方法来探测ASBT蛋白中涉及配体和钠相互作用的氨基酸残基：（4）通过质谱确定ASBT的配体结合结构域;我们将使用选择性光亲和标记来确定配体结合肽序列。通过这些研究获得的信息将显着增加我们的理解，驱动胆汁酸转运的结构相互作用，并进一步我们的溶质载体蛋白的结构知识一般。此外，它可能有助于未来开发针对高胆固醇血症和相关心血管疾病的特定治疗策略。