IDBR: Development of a Spectroscopic Instrument for the Study of Vibrational Relaxation and Local Motion in Biomolecular Systems

摘要：本提案旨在构建一种仪器，该仪器将提供以前无法获得的关于质膜、仿生结构和光收集蛋白质的组织和动力学信息。脂质双分子层和光收集蛋白内的能量耗散尚不清楚，但被认为介导了这两类不同生物分子系统的功能。该项目解决的一个广泛的生物学问题是脂筏结构形成的基本分子基础，以及为什么这种结构随着双层成分的浓度和身份而变化。了解脂筏组织的分子结构基础需要测量脂双分子层组分的粘弹性和分子间相互作用。所提出的仪器将允许测量生物分子系统中的分子运动和热能流。本项目需要设计、建造和表征一种仪器，该仪器将应用刺激发射光谱来研究生物膜和蛋白质的结构和动力学。该仪器将揭示哺乳动物细胞膜的脂质和蛋白质组分如何相互作用以产生负责能量转导，跨膜运输和分子识别的功能组件。该仪器将表征脂质-脂质和脂质-蛋白质的相互作用，这些相互作用控制着脂质双分子层组装的流动性，以及作为化学反应和分子运动驱动力的组分之间的热能流动。该仪器将在双色泵浦中使用可调谐皮秒激光器。探针检测方案，以检查振动能量转移和快速分子尺度运动的双层膜和光收集蛋白质。这样的测量在以前是不可能的。该检测系统具有相敏和短噪声限制特性，可测量1 / 107的透射率变化。由于膜中短寿命复合物的形成和衰变背后的反应动力学是由振动激活的障壁穿越过程控制的，因此使用该仪器获得的信息对于理解与空间异质结构（包括脂筏和蛋白质）相关的动力学至关重要。广泛使用的仪器的创建，推动了脂质双分子层特性和动力学测量的最新技术，将对密歇根州立大学和区域科学界以及全球科学界产生重大影响。PI和合作PI与密歇根州立大学其他部门（如生物化学和分子生物学、食品安全和毒理学、细胞和分子生物学、微生物学和分子遗传学）的教师、附近机构（如萨吉诺谷州立大学、西密歇根大学）的教师以及国际机构（如华沙大学（波兰）、巴斯大学（英国）、新加坡国立大学和陕西师范大学）的教师合作。他们还与联邦研究机构合作，如位于伊利诺伊州尚佩恩的美国陆军工程研究与发展中心。扩大在科学领域代表性不足的群体的参与是至关重要的。密歇根州立大学有多个项目来联系高中中代表性不足的群体（密歇根州立大学高中荣誉科学/数学/工程计划（HSHSP）， ACS项目SEED），本科生（全国黑人化学家和化学工程师组织（NOBCChE）， DREW/TAC计划），研究生(NOBCChE，密歇根州立大学非裔美国人，拉丁裔(a)/墨西哥裔(a)，亚洲/太平洋美国人，美国原住民（ALANA）计划)和研究生水平（密歇根州立大学资助的少数民族博士后奖学金）。PI和联合PI在多个层面上与这些项目合作，并继续努力为所有群体的学生提供实践研究的机会和指导。

AbstractThis proposal is for the construction of an instrument that will provide previously unobtainable information on the organization and dynamics of plasma membranes, biomimetic structures, and light harvesting proteins. The dissipation of energy within lipid bilayers and light harvesting proteins is not well understood but is thought to mediate the function of these two different classes of biomolecular systems. One of the broad biological issues this project addresses is the fundamental, molecular basis for the formation of lipid raft structures, and why such structures vary with the concentrations and identities of the bilayer constituents. Understanding the molecular structural basis for lipid raft organization requires that the viscoelastic properties and intermolecular interactions of the lipid bilayer constituents can be measured. The proposed instrumentation will allow for the measurement of molecular motion and thermal energy flow in biomolecular systems. This project entails designing, constructing, and characterizing an instrument that will apply stimulated-emission spectroscopy to the study of structure and dynamics of biological membranes and proteins. The instrument will reveal how the lipid and protein components of the mammalian cell membrane interact to yield functional assemblies that are responsible for energy transduction, transmembrane transport, and molecular recognition. The instrument will characterize the lipid-lipid and lipid-protein interactions that control the fluidity of the lipid bilayer assembly and the flow of thermal energy between components that serves as the driving force for chemical reactions and molecular motion.The instrument will employ tunable picosecond lasers in a two-color pump?probe detection scheme to examine vibrational energy-transfer and fast molecular-scale motions in bilayer membranes and light harvesting proteins. Such measurements have not been possible before. The detection system is phase-sensitive and shot-noise-limited to measure transmission changes of one part in 107. Because the reaction dynamics underlying the formation and decay of short-lived complexes in membranes are controlled by vibrationally activated barrier-crossing processes, the information obtained with the proposed instrument is crucial to reaching an understanding of the dynamics associated with spatially heterogeneous structures, including lipid rafts and proteins. The creation of broadly accessible instrumentation that advances the state of the art in the measurement of lipid bilayer properties and dynamics will have a major impact on the MSU and regional scientific communities as well as on the global scientific community. The PI and co-PIs collaborate with faculty in a host of other MSU departments (e.g. Biochemistry and Molecular Biology, Food Safety and Toxicology, Cell and Molecular Biology, Microbiology and Molecular Genetics), faculty from nearby institutions (e.g. Saginaw Valley State University, Western Michigan University) and from international institutions (e.g. University of Warsaw (Poland), University of Bath (UK), National University of Singapore, and Shaanxi Normal University (PRC)). They also collaborate with Federal research organizations such as the US Army Engineer Research and Development Center in Champaign, IL. Broadening inclusion of under-represented groups in science is critically important. Michigan State University has multiple programs in place to connect with under-represented groups at the high school (MSU High School Honors Science/Math/Engineering Program (HSHSP), ACS Project SEED), undergraduate (National Organization of Black Chemists and Chemical Engineers (NOBCChE), DREW/TAC Program), graduate (NOBCChE, MSU African-American, Latino(a)/Chicano(a), Asian/Pacific American, and Native American (ALANA) Program) and post-graduate levels (MSU sponsored minority post-doctoral fellowships). The PI and the co-PIs have collaborated with these programs on several levels and continue to strive to provide students from all groups with hands-on research opportunities and mentoring.