SPECTROSCOPIC INVESTIGATIONS OF BIOLOGICAL SYSTEMS

我们的研究目标是了解生物过程和 现象的物理机制和探索适应的物理机制 物理技术解决生物学中的问题。更具体的目标和 我们自己正在解决的问题如下： 1)蛋白质-叶绿素复合体的能量转换机制 从光合细菌的膜中溶解出来的和 结构函数关系的表征与测定 这个复合体被称为反应中心(RC)。具体目标是：(A) 完成RC蛋白的氨基酸序列，(B)获得 用X射线衍射法研究RC的三维结构，(C)~ 研究蛋白质修饰对结构和结构的影响 (D)将调查范围扩大到其他膜 蛋白质。一些发现和方法预计将是 与其他电子转移过程有关，最明显的是呼吸系统 线粒体中的链状结构。 2.)生物分子的电子结构：我们想要扩展我们的 RCS的非血红素铁中心对原子(分子)的理解 水平。将使用EPR和Endor实验来确定参数 表征了Fe2+的电子态。 3.)生物大分子的结晶，特别强调 蛋白质。我们的目标是了解导致 单晶的形成。的三个时间阶段 结晶，即a.)成核作用，b.)形核后生长，以及c.) 停止生长，将在水溶模型上进行研究 化合物。溶菌酶。我们计划将这种方法扩展到其他蛋白质， 包括完整的膜蛋白。我们的长期目标是 在一个系统的过程中获得大的，高质量的X射线晶体 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.