Molecular Mechanisms of Membrane Transport

膜运输的分子机制

• 批准号: 7741727
• 负责人: DAVID S CAFISO
• 金额: $ 28.49万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-09-06 至 2012-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7741727
• 关键词: Action Potentials; Active Biological Transport; Address; Affinity; Antibiotics; Apoptosis; Bacteria; Binding; Boxing; Carrier Proteins; Cell membrane; Cholera; Citrates; Complex; Coupling; Crystallization; Development; Electron Spin Resonance Spectroscopy; Electrons; Environment; Equilibrium; Escherichia coli; Event; Family; Ferrichrome; Goals; Gram-Negative Bacteria; Growth; Ions; Iron Chelating Agents; Knowledge; Ligands; Lipids; Maintenance; Measurement; Membrane; Membrane Proteins; Membrane Transport Proteins; Meningitis; Metabolism; Modeling; Molecular; Molecular Models; N-terminal; Normal Cell; Nutrient; Pathogenicity; Pertussis; Physiological; Polyethylene Glycols; Process; Proteins; Relative (related person); Research; Resolution; Shapes; Signal Transduction; Site; Spin Labels; Structural Models; Structure; Surface; System; Testing; Thermodynamics; Trace Elements Nutrition; Transmembrane Transport; Transport Process; Vitamin B 12; Work; base; design; fascinate; hatching; insight; interest; molecular modeling; mutant; pathogen; periplasm; protein complex; protein folding; protein function; protein protein interaction; protein structure; public health relevance; solute; success; uptake

DESCRIPTION (provided by applicant): Active membrane transport is a critical process for normal cell metabolism, including the maintenance of ion-gradients, osmotic balance, action potentials and apoptosis. The proposed work will address key questions regarding the mechanisms of nutrient uptake in Escherichia coli and other Gram negative bacteria. In E. coli, rare nutrients are sequestered by specific outer- membrane proteins that derive energy by coupling to the inner-membrane protein TonB. These TonB-dependent transporters include BtuB, which is responsible for vitamin B12 transport, and FhuA, FecA and FepA, which are responsible for the transport of various forms of chelated iron. TonB-dependent transporters are abundant in Gram negative bacterial and are critical to the success of many bacterial pathogens, such as the bacteria that result in meningitis, cholera and pertussis. Because they are unique to bacteria, these transporters are a logical target for the development of new classes of antibiotics. High-resolution crystallographic models have been obtained for a number of TonB-dependent transporters; however, the mechanisms by which transport takes place is unclear. The proposed work will utilize site-directed spin labeling and EPR spectroscopy to test models for the molecular mechanisms of TonB-dependent transport, determine the mechanisms of transmembrane signaling and determine the mechanisms by which the transporter-TonB interaction is regulated. Finally, the structure and dynamics of these transporters (which are based upon 2-barrels) are influenced by both solute and lipid environment. Because of the critical need to generate and interpret high-resolution structural models of membrane proteins, the proposed work will also quantitate the influence of solutes and lipid environment on the structure of this class of membrane proteins. PUBLIC HEALTH RELEVANCE: The proposed research will determine the molecular mechanisms by which bacteria transport scarce nutrients across their cell membrane. This transport is critical to the survival of bacteria, and it is essential for the success of many bacterial pathogens, such as the bacteria that cause meningitis, cholera and pertussis. Knowledge of these transport mechanisms will assist with the development of new antibiotics that can inhibit bacterial growth.

描述（由申请人提供）：主动膜运输是正常细胞代谢的关键过程，包括维持离子梯度，渗透平衡，动作电位和凋亡。拟议的工作将解决有关大肠杆菌和其他革兰氏阴性细菌中营养摄取机制的关键问题。在大肠杆菌中，稀有营养素是由特异性外膜蛋白隔离的，这些外膜蛋白通过偶联到内膜蛋白TONB来得出能量。这些依赖于TONB的转运蛋白包括负责维生素B12转运的BTUB，以及FHUA，FECA和FEPA，它们负责各种形式的螯合铁的运输。 TONB依赖性转运蛋白在革兰氏阴性细菌中很丰富，并且对于许多细菌病原体的成功至关重要，例如导致脑膜炎，霍乱和百日咳的细菌。由于它们是细菌独有的，因此这些转运蛋白是开发新类抗生素的逻辑靶标。已经获得了许多依赖TONB的转运蛋白的高分辨率晶体学模型。但是，运输发生的机制尚不清楚。所提出的工作将利用位置定向的自旋标记和EPR光谱来测试模型，以确定TONB依赖性转运的分子机制，确定跨膜信号传导的机制，并确定调节转运蛋白-TONB相互作用的机制。最后，这些转运蛋白（基于2桶）的结构和动力学受溶质和脂质环境的影响。由于迫切需要生成和解释膜蛋白的高分辨率结构模型，因此所提出的工作还将量化溶质和脂质环境对这类膜蛋白结构的影响。公共卫生相关性：拟议的研究将确定细菌在其细胞膜上传递稀缺营养的分子机制。这种转运对于细菌的存活至关重要，对于许多细菌病原体的成功，例如引起脑膜炎，霍乱和百日咳的细菌至关重要。了解这些运输机制将有助于开发新的抗生素，这些抗生素可以抑制细菌的生长。