BECKMAN XL-1 ANALYTICAL ULTRACENTRIFUGE

我们计划获得一种最先进的Beckman Optimal(TM)XL-I分析型超速离心机，配备有吸收和瑞利干涉光学元件。马萨诸塞大学目前还没有E型或类似的分析性超速离心机。研究人员小组由八名NIH资助的研究人员组成；七名用户来自马萨诸塞大学伍斯特医学中心，代表三个不同的学术部门。第八名研究人员位于附近的马萨诸塞大学阿默斯特校区，为九个主要用户实现其NIH资助的研究计划的目标，获得XL-I分析性超速离心机是必要的。所有用户都从事生物大分子的定量研究，他们为分子结构的研究带来了广泛的背景和兴趣。由于大分子的结构和行为会随着浓度、溶液成分、pH和温度的不同而显著变化，因此在类似的溶液条件下确定不同的性质通常是至关重要的。分析超速离心法的分析完全满足了这一要求。主要用户正在研究的领域包括1)酵母组蛋白八聚体和SWI/SNF染色质重塑复合体，2)动力蛋白和动力蛋白亚基的性质，3)协作血红蛋白的组装，4)RecA细丝组装，5)G蛋白和交换因子的核苷酸依赖的相互作用，6)副粘病毒膜融合，7)肌肉收缩的结构和调节，以及8)染色质的三维结构分析。总体而言，这九项研究建议涵盖了分析性超速离心机非常适合回答的所有问题，包括样品纯度的测量、构象变化的检测和表征、亚单位化学计量学的确定以及超分子组装的组装和拆解机制的表征。拟议中的仪器购买将满足马萨诸塞大学NIH支持的研究人员的迫切研究需求。

We propose to acquire a state-of-the-art Beckman Optimal (Tm) XL-I analytical ultracentrifuge equipped with both absorbance and Rayleigh interference optics. No Model E or comparable analytical ultracentrifuge is currently available at the University of Massachusetts. The investigator group is composed of eight NIH-funded investigators; seven users are from the University of Massachusetts Medical Center at Worcester and represent three different academic departments. The eighth investigator is located at the nearby University of Massachusetts campus at Amherst Acquisition of a XL-I analytical ultracentrifuge has become necessary for the nine major users to accomplish aims of their NIH-funded research programs. All of the users are engaged in quantitative studies of biological macromolecules and they bring a broad spectrum of backgrounds and interests to the investigation of molecular structure. Because macromolecular structure and behavior Can vary markedly with concentration, solution components, pH, and temperature, it is often essential that different properties be determined under similar solution conditions. Analyses by analytical ultracentrifugation uniquely fulfills this requirement. Areas under investigation by the major users are 1) assembly of yeast histone octamers and the SWI/SNF chromatin remodeling complex, 2) properties of dynamin and dynein subunits, 3) assembly of cooperative Hemoglobins, 4) RecA filament assembly, 5) Nucleotide dependent interactions of G proteins and exchange factors, 6) Paramyxovirus membrane fusion, 7) Structure and regulation of muscle contraction, and 8) analysis of the 3-D structure of chromatin. Cumulatively, these nine research proposals cover the entire range of questions for which the analytical ultracentrifuge is ideally suited to answer, including measurements of sample purity, detection and characterization of conformational changes, determination of subunit stoichiometries, and characterization of assembly and disassembly mechanisms for supramolecular assemblies. The proposed instrument purchase will fulfill acute research needs of NIH-supported investigators at the University of Massachusetts.