ENERGY TRANSDUCTION BETWEEN MEMBRANES

这项研究的目标是了解生物能源 革兰氏阴性杆菌细胞质和外膜之间的转导 细菌，使用大肠杆菌作为模型系统。在大肠大肠杆菌， 细胞质膜能量与以下物质的主动转运偶联 重要的营养素（铁-铁载体复合物和维生素B12） 外膜。虽然我们知道能量转换是通过 通过细胞质膜的电化学电位， 蛋白质TonB、ExbB和ExbD参与该过程， 能量传递机制以及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 转导蛋白尚未阐明。此外，最近的数据 这表明已经确定的其他蛋白质的参与， 只在生物化学上，而不是遗传学上。这项建议的目的是 1.）的人。从遗传学和生物化学两方面来定义 能量转换机制; 2.）确定的功能 在能量的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 与细胞质膜中的能量产生机构接触。 3.）第三章研究ExbB在能量转导中的作用，重点是其 提出的回收活动和其胞质结构域的功能。

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.