Acquisition of an Optima XL-A Analytical Ultracentrifuge

我们向国家科学基金会申请资金购买一台分析型超离心机。这是为了更换我们已经使用了26年的E型超离心机，它几乎不可能维护，而且某些配件也不再生产。此外，在过去的四分之一世纪中，由于光路长度非常短和组件质量的进步，XL-A大大提高了灵敏度。此外，它的输出现在完全由计算机处理，使处理结果更加迅速和可靠。使用该仪器，我们将能够获得分子量，有效部分比体积和沉降常数。这些信息将使我们能够确定多亚基组合的分子结构，更可靠地估计复杂且可能与溶剂成分广泛相互作用的大分子聚集体的组成，并获得蛋白质结合反应的定量参数。具体来说，该仪器将用于获得纤维素酶组分、金属酶和超嗜热菌氧化还原蛋白的“真实”（热力学意义上的）分子量，探索人绒毛膜促性腺激素亚基相互作用，测量酵母烯醇化酶的水合作用和盐结合，以及测量细菌荧光素酶反应中反应物之间的复合物形成。

We are requesting funds from the National Science Foundation to purchase an Analytical Ultracentrifuge. This is to replace our 26-year old Model E ultracentrifuge, which is nearly impossible to maintain and for which certain accessories are no longer produced. Also, the XL-A has greatly increased sensitivity as a result of a very much shorter optical path length and advances in component quality over the last quarter century. Furthermore, its output is now fully computer processed, enabling far more rapid and reliable processing of results. With this instrument, we will be able to obtain molecular weights, effective partial specific volumes and sedimentation constants. These pieces of information will allow us to determine molecular architecture of multisubunit assemblies, more reliably estimate compositions of macromolecular aggregates which are complex and which may interact extensively with solvent constituents, and obtain quantitative parameters of protein association reactions. Specifically, the instrument will be used to obtain "true" (in a thermodynamic sense) molecular weights of cellulase components, metalloenzymes and redox proteins from hyperthermophiles, explore subunit interactions in human choriogonadotropin, measure hydration and salt binding in yeast enolase and measure complex formation between reactants in the bacterial luciferase reaction.