SPECTROSCOPIC INVESTIGATIONS OF BIOLOGICAL SYSTEMS

我们的研究目标是了解生物过程， 现象的物理机制，并探讨适应 物理技术来解决生物学问题。 更具体的目标和 我们正在处理的问题如下： 1.）蛋白质-叶绿素复合体中能量转换的机制 从光合细菌的膜溶解， 结构与功能关系的表征与确定 这个复合物被称为反应中心（RC）。 具体目标是： 完成RC蛋白的氨基酸序列，（B）以获得 通过X射线衍射获得RC的三维结构，（c）至 研究蛋白质修饰对结构和 RC的功能，以及（d）将调查扩展到其他膜 proteins. 预计其中的一些调查结果和方法将 与其他电子转移过程有关，最明显的是呼吸过程。 线粒体中的链。 2.）的情况。生物分子的电子结构：我们希望扩展我们的 理解RC的非血红素铁中心的原子（分子） 水平 EPR和ENDOR实验将用于确定参数 表征Fe 2+的电子状态。 3.）第三章生物大分子的结晶，特别强调 proteins. 我们的目标是了解导致 形成单晶体。 的三个时间阶段 结晶，即，a.）成核，B.）成核后生长，以及c.） 停止生长，将在水溶性模型上进行研究 化合物.溶菌酶 我们计划将该方法扩展到其他蛋白质， 包括整合膜蛋白。 我们的长期目标是 在一个系统的程序，以获得大，高品质的晶体， 衍射研究

Our research objectives are to understand biological processes and phenomena in terms of physical mechanisms and to explore the adaptation of physical techniques to problems in biology. The more specific goals and problems to which we are addressing ourselves are the following: 1.) The mechanism of energy conversion in a protein-chlorophyll complex solubilized frm the membranes of photosynthetic bacteria and the characterization and determination of the structure function relation of this complex called the reaction center (RC). Specific aims are to: (a) complete the amino acid sequence of the RC protein, (b) to obtain the three-dimensional structure of the RC by X-ray diffraction, (c) to investigate the effect of protein modifications on the structure and funciton of the RC, and (d) to extend the investigation to other membrane proteins. Some of the findings and methodologies are expected to be relevant to other electron-transfer processes, most notably the respiratory chain in mitochondria. 2.) Electronic Structure of Biomolecules: We want to extend our understanding of the non-heme iron center of RCs to the atomic (molecular) level. EPR and ENDOR experiments will be used to determine the parameters characterizing the electronic state of the Fe2+. 3.) Crystallization of Biological Macromolecules, with special emphasis on proteins. Our goal is to understand the detailed mechanisms leading to the formation of single crystals. The three temporal phases of crystallization, i.e., a.) nucleation, b.) post-nucleation growth, and c.) cessation of growth, will be investigated on the water-soluble model compound. lysozyme. We plan to extend the methodology to other proteins, including integral membrane proteins. The long-term objective is to arrive at a systematic procedure to obtain large, high-quality crystals for X-ray diffraction studies.