Control of Membrane Protein Structure and Function by Sequence and Lipid

智力优势蛋白质嵌入在细胞周围的脂质膜中，控制细胞与环境的相互作用。它们在细胞内外运输分子，并在外部环境和细胞内部之间传递信息。然而，关于膜蛋白结构如何允许它们执行这些功能，还有很多未知。回答这个问题的关键是了解跨膜（TM）螺旋的行为，这是在膜蛋白的膜嵌入部分中发现的主要结构。TM螺旋是从膜的一侧交叉到另一侧的氨基酸的螺旋序列。本提案的目标是确定TM螺旋的氨基酸序列和膜中脂质的化学组成如何控制TM螺旋在不同结构和功能状态之间相互转换的能力。特别是，氨基酸序列和脂质成分如何影响TM螺旋在膜中的位置，以及TM螺旋在膜内的位置如何改变功能将被检查。为此，该项目将定义TM螺旋的氨基酸突变，以可控的方式改变膜内TM螺旋的位置。荧光方法，在以前的研究中开发的，然后将被用来测量TM螺旋在膜中的位置。人工TM螺旋的行为，其中仔细控制的序列可以回答有关序列/结构关系的精确问题，将在人工脂质膜中进行研究，其中脂质成分和其他环境条件可以变化。此外，TM螺旋与天然膜蛋白中发现的氨基酸序列将进行研究，结合相应的完整的膜蛋白，以证明如何获得的知识可以用来定义TM螺旋定位和功能之间的关系。更广泛的影响该项目将对未来科学家的职业发展产生广泛的影响，包括少数民族学生，在教育层面上，通过培训研究生和本科生（包括通过与其他当地机构的联系）进行研究，荧光原理，膜结构和功能。在实验室中使用的独特荧光猝灭方法的培训将有助于这些学生在毕业后传播这些技术，并将其应用于未来的职业生涯。通过定义其他实验室可以使用的策略来接近膜蛋白螺旋结构与功能的关系，也将对植物和细菌对有毒化合物的生物修复（涉及膜蛋白转运蛋白），生物材料应用（其中膜蛋白被研究为超敏生物传感器）和生物电子学应用产生广泛的影响。

Intellectual MeritProteins embedded in the lipid membranes that surround cells control the interaction of cells with their environment. They transport molecules in and out of cells and transmit messages between the external environment and the interior of the cell. However, there is much that is not known about how membrane protein structure allows them to carry out these functions. A key to answer this question is to understand the behavior of transmembrane (TM) helices, the predominant structure found in the membrane-embedded portion of membrane proteins. TM helices are helical sequences of amino acids that cross from one side of the membrane to the other. The goal of this proposal is to determine how the amino acid sequence of TM helices and the chemical composition of the lipids in a membrane control the ability of TM helices to interconvert between different structural and functional states. In particular, how amino acid sequence and lipid composition affect the position of a TM helix in membranes, and how TM helix position within the membrane alters function will be examined. To do this, the project will define amino acid mutations of TM helices that alter the position of TM helices within a membrane in a controllable fashion. Fluorescence methods, developed in previous studies, will then be used to measure the position of TM helices in a membrane. The behavior of artificial TM helices, in which carefully controlled sequences can answer precise questions concerning the sequence/structure relationship, will be studied in artificial lipid membranes in which lipid composition and other environmental conditions can be varied. In addition, TM helices with the amino acid sequences found in natural membrane proteins will be studied, in conjunction with the corresponding intact membrane proteins, in order to demonstrate how the knowledge gained can be used to define the relationship between TM helix positioning and function. Broader ImpactThis project will have a broad impact on career development of future scientists, including minority students, at the educational level by training both graduate and undergraduate students (including via contacts with other local institutions) in the conduct of research, fluorescence principles, and membrane structure and function. Training in the unique fluorescence quenching approaches used in the lab would aid dissemination of these techniques by these students after they graduate and apply them in their future careers. By defining strategies other labs can use to approach the relationship of membrane protein helix structure to function there would also be a broad impact upon bioremediation of toxic compounds by plants and bacteria (which involves membrane protein transporters), biomaterials applications (in which membrane proteins are being studied as hypersensitive biosensors) and bioelectronics applications.