ENERGY TRANSDUCTION BETWEEN MEMBRANES

这项拟议的研究的目标是了解生物能源。 革兰氏阴性杆菌胞质与外膜之间的转导 细菌，以大肠埃希菌为模型系统。在大肠杆菌中， 细胞膜能量与细胞的主动转运有关 重要营养素(铁-铁载体复合体和维生素BL2) 外膜。尽管我们知道能量转换是有能量的 通过细胞质膜的电化学势，以及 蛋白质TonB、ExbB和ExbD参与这一过程，分子 能量转导机制及ExbB和ExbD的作用 不清楚。TonB作为能量转换器的作用已经确立， 然而，它与其他能量相互作用的分子细节 转导蛋白还没有被阐明。此外，最近的数据 暗示了已经确定的其他蛋白质的参与 只是生化的，而不是遗传的。这项提议的目的是 1)从基因和生物化学的角度定义 能量转换机械；2.确定(S)的职能 能量氨基末端的特定氨基酸残基 换能器，TonB。这些是TonB的区域被认为是直接 与细胞膜中的能量产生机械接触。 3.)研究ExbB在能量转导中的作用，重点是其 建议的回收活性及其细胞质结构域的功能。

The goal of the proposed research is to understand biological energy transduction between the cytoplasmic and outer membranes of Gram-negative bacteria, using Escherichia coli as the model system. in E. coli, cytoplasmic membrane energy is coupled to the active transport of important nutrients (iron-siderophore complexes and vitamin Bl2) across the outer membrane. Although we know that energy transduction is energized by the cytoplasmic membrane electrochemical potential, and that the proteins TonB, ExbB, and ExbD participate in that process, the molecular mechanism of energy transduction and the role of ExbB and ExbD are unclear. The role of TonB as energy transducer has been established, however, the molecular details of its interactions with other energy transduction proteins have not been elucidated. Furthermore, recent data suggest the participation of additional proteins which have been defined only biochemically, and not genetically. The aims of this proposal are to 1.) define, both genetically and biochemically, the protein components of the energy transduction machinery; 2.) determine the function(s) of specific amino acid residues in the amino terminus of the energy transducer, TonB. These are the regions of TonB believed to be in direct contact with the energy generating machinery in the cytoplasmic membrane. 3.) Investigate the role of ExbB in energy transduction, focusing on its proposed recycling activity and the function of its cytoplasmic domains.