Structural mechanics of MsbA family ABC transporters

MsbA家族ABC转运蛋白的结构力学

基本信息

批准号：
7269274
负责人：
JOHN Francis HUNT
金额：
$ 28.37万
依托单位：
COLUMBIA UNIV NEW YORK MORNINGSIDE
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-08-01 至 2009-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7269274
关键词：
ATP-Binding Cassette Transporters Active Biological Transport Active Sites Adenosine Triphosphate Adrenoleukodystrophy Affinity Architecture Bacterial Genome Binding Cell membrane Cells Class Communication Conserved Sequence Cystic Fibrosis DNA Sequence Rearrangement Depth Dimerization Disease E coli MsbA protein Energy-Generating Resources Enzymatic Biochemistry Escherichia coli Family Gene Family Genetic Homologous Gene Human Hydrolysis In Vitro Integral Membrane Protein Life Lipids Mechanics Mediating Membrane Methods Microbial Genome Sequencing Molecular Molecular Conformation Molecular Machines Motor Movement Multi-Drug Resistance Mutation Nature Organism P-Glycoproteins Pathway interactions Pharmacology Phospholipids Physiological Play Power stroke Property Proteins Pump Reaction Research Resolution Role Side Staging Stereotyping Structure System Transmembrane Domain Transmembrane Transport Virulence Factors Work dimer efflux pump improved leukemia member prevent reconstitution solute tumor

项目摘要

DESCRIPTION (provided by applicant): ATP-binding cassette (ABC) Transporters represent the molecular architecture most commonly employed by cells to drive the active transport of solutes across membranes using adenosine triphosphate (ATP) as an energy source. ABC Transporters occur in all living organisms and comprise one of the largest gene family in fully sequenced microbial genomes. At least one bacterial ABC Transporter has been shown to be essential for the viability of E. coli, while others have been shown to function as bacterial pathogenicity factors. The aberrant function of human ABC Transporters plays a central role in a variety of diseases including cystic fibrosis, adrenoleukodystrophy, and multidrug resistance in advanced tumors and leukemias. Previous research from my lab has helped to define the mechanism by which the structurally-stereotyped ABC motor domains in ABC Transporters employ the binding and hydrolysis of ATP to perform mechanical work. Using combined enzymological and crystallographic studies, we showed that ATP binding to conserved sequence motifs drives the formation an "ATP-sandwich dimer" by the ABC motor domains. This ATP-induced dimerization is believed to represent the power-stroke of the pumps because the physical movements of the ABC's during dimer formation is hypothesized to drive the essential conformational rearrangements in the transmembrane domains that mediate solute transport. We propose to extend our earlier studies of the mechanochemical reaction cycle of ABC Transporter motor domains to characterize the structural details of these allosteric conformational changes in the transmembrane domains that drive solute transport in one specific class of ABC efflux pumps. Our proposed studies involve a comgination of genetic, enzymological, and crystallographic approached to this fundamental biophysical problem. Successful completion of this work would provide deeper structural and mechanistic understanding that would facilitate studies on the molecular pharmacology of the disease-causing proteins in the ABC Transporter superfamily.

描述（由申请人提供）： ATP 结合盒 (ABC) 转运蛋白代表细胞最常用的分子结构，以三磷酸腺苷 (ATP) 作为能源驱动溶质跨膜主动转运。 ABC 转运蛋白存在于所有生物体中，是完全测序的微生物基因组中最大的基因家族之一。至少一种细菌 ABC 转运蛋白已被证明对于大肠杆菌的生存至关重要，而其他转运蛋白已被证明可作为细菌致病因子。人类 ABC 转运蛋白的异常功能在多种疾病中发挥着核心作用，包括囊性纤维化、肾上腺脑白质营养不良以及晚期肿瘤和白血病的多药耐药性。我实验室之前的研究帮助定义了 ABC 转运蛋白中结构定型的 ABC 运动域利用 ATP 的结合和水解来执行机械功的机制。通过结合酶学和晶体学研究，我们发现 ATP 与保守序列基序的结合驱动 ABC 运动域形成“ATP 夹心二聚体”。这种 ATP 诱导的二聚化被认为代表了泵的动力冲程，因为假设二聚体形成过程中 ABC 的物理运动驱动介导溶质转运的跨膜域中的基本构象重排。我们建议扩展我们对 ABC 转运蛋白运动域的机械化学反应循环的早期研究，以表征跨膜域中这些变构构象变化的结构细节，这些跨膜域驱动一类特定类别的 ABC 外排泵中的溶质转运。我们提出的研究涉及遗传、酶学和晶体学方法的结合，以解决这一基本的生物物理问题。这项工作的成功完成将提供更深入的结构和机制理解，从而促进 ABC 转运蛋白超家族中致病蛋白的分子药理学研究。