Intrinsic Fluorescence for Protein Crystal Scoring

x射线晶体学是测定蛋白质结构的主要工具。由于基因组学即将产生大量用于结构测定的蛋白质，因此必须进行相应的大量x射线衍射实验。然而，x射线分析是劳动密集型的，因此从经济学的角度来看，从大量候选蛋白质晶体中选择哪种蛋白质晶体进行x射线分析变得很重要。因此，希望有一种快速的方法来评价蛋白质晶体具有衍射质量的可能性。我们提出了一种基于蛋白质本征荧光的蛋白质晶体评分方法和仪器。对三种蛋白质的初步结果表明，单晶荧光光谱与其x射线晶体学测定的内部顺序之间存在相关性。在第一阶段，我们建议在大量蛋白质晶体上验证荧光与衍射性质相关的假设。我们预计，作为第一阶段的结果，一种快速的蛋白质晶体评分方法将被开发出来。在第二阶段，设想的评分方法将被用作构建自动化仪器原型的核心，该仪器可适用于各种高通量蛋白质晶体生长技术。建议的商业应用：在即将到来的蛋白质组学时代，对蛋白质晶体衍射x射线能力的快速评估的需求将是巨大的。目前，还没有一种方法可以对蛋白质晶体进行快速评分。设想的荧光分析将填补高通量结晶技术和劳动密集型x射线衍射实验之间的空白，并将为研究人员提供一种快速、低成本的蛋白质晶体评分技术。

X-ray crystallography is the main tool for determining protein structure. Since genomics is on the verge of creating a large number of proteins for structure determination, a corresponding large number of X-ray diffraction experiments will have to be performed. However, X-ray analysis is labor intensive so that the question of which protein crystal to choose for X-ray analysis from the vast pool of candidates becomes important from an economics standpoint. Therefore, it is desirable to have a rapid method to score protein crystals regarding their likelihood for being of diffraction quality. We propose to develop a method and apparatus for protein crystal scoring which is based on intrinsic fluorescence of proteins. Preliminary results obtained for three proteins demonstrated correlation between fluorescence spectra of single crystals and their internal order as determined by X-ray crystallography. During Phase I, we suggest to verify the hypothesis of correlation between fluorescence and diffraction properties on a large number of protein crystals. We anticipate that a rapid method for protein crystal scoring will be developed as a result of Phase I. In Phase II, the envisioned scoring method will be used as a core for building a prototype of an automated instrument which can be adapted for a variety of high throughput protein crystal growth technologies. PROPOSED COMMERCIAL APPLICATIONS: In the coming era of proteomics, the need for rapid assessment of protein crystals with respect to their ability to diffract X-rays will be enormous. At the present time, there is no method for rapid scoring of protein crystals. The envisioned fluorescence assay will fill the gap between high throughput crystallization technologies and labor intensive X-ray diffraction experiments and will provide researchers with a rapid and low cost technique for scoring protein crystals.