Collaborative Research: Structure and Function of the Nodulin 26 Aquaglyceroporin

合作研究：Nodulin 26 水甘油孔蛋白的结构和功能

• 批准号: 9904978
• 负责人: Daniel Roberts
• 金额: $ 29.1万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9904978&HistoricalAwards=false
• 关键词: Collaborative; Research; Structure; Function; Nodulin

9904978Roberts/MitraDuring the formation of nitrogen-fixing symbioses between legumes and rhizobia bacteria, a set of genes is induced that encode "nodulins", proteins that aid in the establishment and maintenance of the symbiosis. Nodulin 26 is among the nodulins that are targeted to the specialized symbiosome membrane that encloses the endosymbiotic bacteroid and mediates metabolite exchange with the host. Nodulin 26 is a member of the MIP/aquaporin channel family, which includes a variety of proteins that flux water or uncharged solutes. The protein has emerged as the prototype of a unique plant MIP subfamily that has an unusual multifunctional transport profile, including a low intrinsic water transport rate compared to other aquaporins, as well as the ability to flux uncharged solutes such as glycerol. The purpose of this collaborative research (with Roberts 9904978) is to investigate the structural details of nodulin 26 that allow it to function as a multifunctional aquaglyceroporin. The goals are 1. The rational design of nodulin 26 mutants to identify residues/domains that determine the single channel rate and selectivity of transport (Roberts); 2. The purification and membrane reconstitution of soybean nodulin 26 (Roberts) for crystallographic structural analyses (Mitra); and 3. The functional analysis of a nodulin 26 ortholog from the genetically tractable model legume Lotus japonicus (Roberts). The recent discovery of aquaporin membrane proteins has revolutionized our understanding of how biological membranes facilitate water and neutral solute transport. Aquaporins are a diverse family comprised of dozens of members, each with discreet functional properties tailored for its biological role. The structural reasons for these diverse functional properties have yet to be unraveled. This collaborative project between a membrane protein cystallographer and a plant biochemist will provide a detailed structural analysis of nodulin 26, a unique aquaporin specifically expressed during nitrogen fixing symbioses. This work will shed light on the structural features that enable nodulin 26 to be a multiselective transporter, and also will provide more fundamental information on the structural features that determine aquaporin activity and selectivity.

9904978 Roberts/Mitra在豆科植物和根瘤菌之间形成固氮共生体的过程中，一组编码“结瘤蛋白”的基因被诱导，这种蛋白质有助于共生体的建立和维持。 结瘤蛋白26是靶向封闭内共生类细菌并介导与宿主的代谢物交换的专门共生体膜的结瘤蛋白之一。 Nodulin 26是MIP/水通道蛋白家族的成员，其包括多种使水或不带电溶质流动的蛋白质。 该蛋白已成为一个独特的植物MIP亚家族的原型，该亚家族具有不寻常的多功能运输特性，包括与其他水通道蛋白相比低的内在水运输速率，以及通量不带电溶质如甘油的能力。 这项合作研究（与Roberts 9904978）的目的是研究Escherulin 26的结构细节，使其能够作为多功能水甘油孔蛋白发挥作用。 目标是1。合理设计的26突变体，以确定残基/结构域，决定单通道速率和选择性的运输（罗伯茨）; 2.用于晶体结构分析的大豆甜蛋白26（Roberts）的纯化和膜重构（Mitra）;和3.来自遗传上易处理的模式豆科植物百脉根（Roberts）的一个百脉根素26直向同源物的功能分析。 最近水通道蛋白膜蛋白的发现彻底改变了我们对生物膜如何促进水和中性溶质转运的理解。 水通道蛋白是一个由数十个成员组成的多元化家族，每个成员都具有为其生物学作用量身定制的谨慎功能特性。 这些不同的功能特性的结构原因尚未解开。这个膜蛋白cystallographer和植物生物化学家之间的合作项目将提供一个详细的结构分析的napulin 26，一个独特的水通道蛋白，特别是在固氮共生过程中表达。 这项工作将揭示的结构特征，使cetulin 26是一个多选择性转运蛋白，也将提供更多的基本信息的结构特征，决定水通道蛋白的活性和选择性。