ANALYTICAL ULTRACENTRIFUGE FOR MACROMOLECULAR STUDIES

描述了一种同时具有干涉和吸收光学的分析性超离心机Beckman Optima XL-I的性质和能力，普渡大学的一组研究科学家将使用它来研究生物重要系统中大分子之间的相互作用。收购这台仪器是在一个大分子生物物理研究中心组装一系列仪器计划的一部分。这一系列仪器目前包括一台表面等离子体共振仪、一台等温量热仪和一台已有十年历史的Beckman Model XL-A型分析超速离心机。该中心的未来发展目标是增加最先进的荧光、FTIR和拉曼光谱仪，以及停流快速反应仪器。这项XL-I分析性超速离心的建议是由六名研究人员提交的，他们参与了蛋白质-蛋白质、蛋白质-核酸、蛋白质-配体和蛋白质-膜相互作用的研究。这些研究人员在高分辨率晶体结构研究以及生物化学、生物物理学和分子遗传学方面拥有专业知识，他们感兴趣的是用生物物理测量来补充他们的结构结果，这些测量可以阐明大分子复合体组装的细节，与配体底物或效应器相互作用状态的变化，或者通过模拟细胞信号状态的修饰。还建议研究大分子络合物的稳定性，探索膜蛋白单分散制备的条件，以帮助这些困难体系的结晶。Beckman XL-A的初步研究已经证明了分析性超速离心法在各种系统中的应用，包括：膜蛋白与其可溶性蛋白的结合亲和力、动物病毒的组装、信号转导蛋白的相互作用、毒素与其细胞受体之间的相互作用以及用于跨膜转运的大蛋白复合体的组装。XL-I将把研究范围扩大到那些涉及较弱相互作用的研究，以及样品的光学特性不适合XL-A吸收光学的研究，并将补充和扩展普渡大学通过结构和生物物理方法获得的信息。

The properties and capabilities are described of an analytical ultracentrifuge, Beckman Optima XL-I, with both interference and absorption optics, that will be used by a group of Purdue research scientists to investigate the interactions between macromolecules in biologically important systems. The acquisition of this instrument is part of a plan to assemble an array of instruments in a center for biophysical studies of macromolecules. This array of instruments currently includes a surface plasmon resonance instrument, an isothermal calorimeter, and a ten-year old Beckman Model XL-A analytical ultracentrifuge. Future development of this center targets the addition of state-of-the-art fluorescence, FTIR and Raman spectrometers, plus a stopped flow rapid reaction instrument. This proposal for the XL-I analytical ultracentrifuge is submitted by a group of six investigators involved in studies of protein-protein, protein-nucleic acid, protein-ligand and protein- membrane interactions. These investigators have expertise in high resolution crystallographic structural studies as well as in biochemistry, biophysics and molecular genetics, and are interested in complementing their structural results with the biophysical measurements that can illuminate the details of assembly of large complexes, changes in interaction states with ligand substrates or effectors or with modifications that mimic cellular signaling states. Investigations of stability of large complexes and search for conditions of monodisperse preparations of membrane proteins are also proposed, as an aid to the crystallization of these difficult systems. Initial studies with the Beckman XL-A have demonstrated the usefulness of analytical ultracentrifugation in a wide variety of systems including: the binding affinity of membrane proteins for their soluble counterparts, assembly of animal viruses, signal transduction protein interactions, interactions between toxins and their cellular receptors as well as the assembly of large protein complexes for transmembrane transport. The XL-I will extend the range of studies into those involving weaker interactions as well as to studies where the optical characteristics of the samples are inappropriate for the absorption optics of the XL-A and will compliment and extend the information obtained by both structural and biophysical methods at Purdue.