Ultra-High Resolution Structure and Dynamics of Bilayer Bound Polypeptides

9317111 Cross博士将继续发展固态核磁共振波谱，以确定经历各向异性环境的样品中的大分子结构和动力学。这里的努力集中在肽结合在脂质双分子层，其中的整体运动仅限于轴向旋转的双分子层正常。局部运动将被详细描述，并将寻求对可能超出肽进入其环境的相关运动进行彻底的研究。非常高分辨率的结构信息将从取向约束中获得，这已经被证明具有非常高的精度。通过这样的动态和结构表征，希望可以更详细地了解多肽主链的势能面。此外，动力速率和动力速率之间的相关性可能导致前所未有的结构动力学和功能之间关系的描述。为了实现这些目标，各种固态核磁共振技术将被改进并与独特的样品制备方案相结合，这些方案既可以定向脂质双分子层及其宿主肽，也可以定向特定位置的同位素标记分子。对于那些不易用更传统的方法，如x射线衍射来研究的蛋白质和其他分子的大分子结构的测定方法将继续发展。这里采用的方法将利用具有一维顺序的样品的核共振光谱，例如定向膜。通过这种方式，所有分子都相对于仪器的磁场排列，并且很容易实现结构约束。膜结合蛋白是一类非常重要的生物大分子，在活组织中负责细胞间的通讯。对于x射线衍射来说，很难形成这些蛋白质和构成其膜环境的脂质分子的共晶。然而，已经有可能形成均匀排列的样品用于核磁共振波谱，因此，该方法有望在这类重要蛋白质的结构测定中发挥非常重要的作用。＊＊＊

9317111 Cross Dr. Cross will continue the development of solid state NMR spectroscopy for the determination of macromolecular structure and dynamics in samples experiencing an anisotropic environment. The efforts here focus on peptides bound in lipid bilayers where the global motions are restricted to the axial rotation about the bilayer normal. Local motions will be characterized in detail and a thorough investigation of correlated motions that may extend beyond the peptide into its environment will be sought. Very high resolution structural information will be obtained from orientational constraints which have already been shown to have a very level of accuracy. Through such a dynamic and structural characterization it is hoped that a more detailed view of the potential energy surfaces of the polypeptide backbone can be achieved. Furthermore, correlations between dynamic rates and kinetic rates may lead to unprecedented descriptions of relationships between structure dynamics and function. To achieve these goals a variety of solid state NMR techniques will be refined and combined with unique sample preparation schemes that both orient lipid bilayers and their host peptides as well as specific site isotopically labeled molecules. %%% The development of methods for the determination of macromolecular structure for those proteins and other molecules that are not easily studied by the more traditional methods, such as x ray diffraction will be continued. The approach taken here will utilize Nuclear Resonance spectroscopy of samples that have one dimensional order, such as an oriented film. In this way all molecules are aligned with respect to the magnetic field of the instrument and structural constraints are readily achieved. Membrane bound proteins are a very important class of biological macromolecules that are responsible for much of the communication between cells in living tissue. For x ray diffraction it has been very difficult to form cocrystals of these proteins and the lipid molecules that make up their membrane environment. However, it has been possible to form uniformly aligned samples for the NMR spectroscopy and therefore, this method is expected to play a very important role in the structure determination of this important class of proteins. ***