Molecular Organization of the Organic Cation-Proton Exchanger, MATE1

有机阳离子-质子交换器的分子组织，MATE1

• 批准号: 8326653
• 负责人: GEOFFREY A CHANG
• 金额: $ 47.6万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-30 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8326653
• 关键词: Amino Acids; Apical; Binding; Binding Sites; Biological; Carrier Proteins; Cations; Charge; Computing Methodologies; Crystallization; Data; Development; Drug Design; Drug Interactions; Drug Kinetics; Epithelial; Epithelial Cells; Epithelium; Face; Family; Family member; Generations; Hand; Hepatic; Homology Modeling; Human; Kidney; Length; Ligand Binding; Ligands; Liver; Maps; Mediating; Methods; Modeling; Molecular; Molecular Profiling; Morbidity - disease rate; Organ; Organic Cation Transporter; Pathway interactions; Peptides; Pharmaceutical Preparations; Pharmacodynamics; Physiological; Play; Process; Program Development; Protein Family; Proteins; Proteomics; Protons; Quantitative Structure-Activity Relationship; Role; Series; Site; Solutions; Source; Structure; Structure-Activity Relationship; Substrate Interaction; Surface; Testing; Toxin; Transport Process; Work; base; clinically significant; database design; design; drug development; extracellular; family structure; inhibitor/antagonist; luminal membrane; member; molecular dynamics; mortality; novel; pharmacophore; predictive modeling; preempt; protein aminoacid sequence; protein structure; public health relevance; research study; three dimensional structure

DESCRIPTION (provided by applicant): The liver and kidney excrete from the body a wide array of positively charged organic molecules of physiological, pharmacological and toxicological significance. Carrier-mediated secretion of these "organic cations" (OCs), particularly by the kidney, has a profound influence on the pharmacokinetics of these compounds and, importantly, OC secretion is the site of many clinically significant drug-drug interactions. The active and rate-limiting step in OC secretion involves the carrier-mediated exit of accumulated OCs across the luminal membrane of renal and hepatic epithelia. The molecular identify of this process involves the newly identified Multidrug And Toxin Extrusion proteins, MATE1 and MATE2-K. Although now clearly understood to play a significant role in OC secretion, virtually nothing is known about the molecular determinants of substrate interaction with these transporters. In this revised proposal, we take advantage of the recent solution of the x- ray structure of a prototypic member of the MATE family of transport protein (NorM). We have used the NorM structure to develop a homology model of human MATE1 and, in this proposal, we outline two sets experiments designed to develop a predictive model of drug interaction with MATE transporters. In Aim 1, we take a ligand-based approach to develop 3D-QSAR/pharmacophore models of substrate/inhibitor interaction with MATE1 and MATE2-K. These data will be interpreted in the context of parallel studies on the integrated activity of these transporters in epithelial models of renal secretion (which, in turn, will be interpreted in the context of studies on the differential distribution of these transporters in human kidney). Aim 2 will employ a target-based approach, using site-directed studies to probe the topology and surface accessibility of MATE1, thereby testing predictions arising from our homology model, and establishing a database designed to probe the functional structure of the protein as determined in a parallel effort to solve the x-ray structure of human MATE1. Aim 2 will also study the substrate translocation pathway of MATE1 in studies that apply (i) proteomic methods to identify peptides and amino acid residues that specifically interact with a photoactivatable probe of the OC/H+ exchanger; and (ii) apply computational methods (steered molecular dynamics) to identify amino acid residues that influence substrate translocation. These studies will play a critical role in establishing models that accurately predict and, ideally, preempt unwanted interactions of cationic drugs in both the kidney and liver. PUBLIC HEALTH RELEVANCE: The kidney and liver actively secrete many drugs from the body, and unwanted drug-drug interactions at the sites of secretion in these organs are a source of substantial morbidity and mortality. The rate-limiting step in the secretion of cationic drugs by the human liver and kidney involves the mediated exchange of organic cations (OCs) for hydrogen ion (H+), a transport process that, until recently, was undescribed at the molecular level. Recent work identified two transporters, MATE1 and MATE2-K, as these "OC/H+ exchangers." Despite their biological importance, and their clinical significance in humans, virtually nothing is known about the relationship of structure and function for these transporters. In this proposal, we outline experiments that will establish the 3D structure of human MATE transporters, identify specific sites within these proteins that influence drug binding, and develop predictive models of substrate/inhibitor interaction with MATE transporters. The results of these studies will help predict and, ideally, preempt unwanted drug-drug interactions in both the kidney and liver, and can be expected to assist in development of programs of structure-based rational drug design.

描述（由申请人提供）：从体内的肝脏和肾脏排泄，生理，药理和毒理学意义上有各种带正电荷的有机分子。载体介导的这些“有机阳离子”（OC）的分泌，特别是肾脏，对这些化合物的药代动力学产生了深远的影响，重要的是，OC分泌是许多临床上重要的药物相互作用的所在地。 OC分泌中的主动和限速步骤涉及载有OC的载体介导的OC跨肾上皮和肝上皮的腔膜的出口。该过程的分子识别涉及新鉴定的多药和毒素挤出蛋白Mate1和Mate2-K。尽管现在清楚地理解在OC分泌中起着重要作用，但实际上对与这些转运蛋白的底物相互作用的分子决定因素几乎一无所知。在这项修订的建议中，我们利用了运输蛋白伴侣家族（Norm）的原型成员的X射线结构的最新解决方案。我们已经使用规范结构来开发人类MATE1的同源模型，在此提案中，我们概述了两组实验，旨在开发与伴侣转运蛋白的药物相互作用的预测模型。在AIM 1中，我们采用了基于配体的方法来开发与MATE1和MATE2-K的底物/抑制剂相互作用的3D-QSAR/PharmaCochore模型。这些数据将在肾分泌的上皮模型中对这些转运蛋白综合活性的平行研究进行解释（反过来，这将在人类肾脏中这些转运蛋白的差分分布的背景下进行解释）。 AIM 2将采用基于目标的方法，利用站点指导的研究来探测MATE1的拓扑和表面可及性，从而测试由我们的同源性模型产生的预测，并建立一个旨在探测蛋白质的功能结构的数据库，以在平行的工作中确定蛋白质的功能结构，以解决人类Mate1的X射线结构。 AIM 2还将研究MATE1在应用（i）蛋白质组学方法的研究中鉴定肽和氨基酸残基的底物易位途径，这些方法与OC/H+交换剂的光活化探针特别相互作用； （ii）应用计算方法（转导的分子动力学）来识别影响底物易位的氨基酸残基。这些研究将在建立准确预测肾脏和肝脏中阳离子药物的不良相互作用的模型中起关键作用。 公共卫生相关性：肾脏和肝脏积极分泌许多药物，在这些器官中分泌部位的不良药物相互作用是大量发病率和死亡率的来源。人肝脏和肾脏分泌阳离子药物的速率限制步骤涉及氢离子（H+）的有机阳离子（OC）的介导的交换，直到最近，该传输过程仍未在分子水平上进行。最近的工作确定了两个转运蛋白MATE1和MATE2-K，是这些“ OC/H+交换器”。尽管它们的生物学重要性及其在人类中的临床意义，但实际上对这些转运蛋白的结构和功能关系一无所知。在此提案中，我们概述了将建立人类配偶转运蛋白的3D结构的实验，确定这些蛋白质中影响药物结合的特定位点，并开发出与伴侣转运蛋白的底物/抑制剂相互作用的预测模型。这些研究的结果将有助于预测肾脏和肝脏中的不必要的药物相互作用，并有望有助于开发基于结构的理性药物设计计划。