STRUCTURE FUNCTION & BIOSYNTHESIS OF RESPIRATORY ENZYMES

这项提议的目标是定义动力机制 和生理作用的各种氧化还原酶和 甲基营养和自养中发现的电子载体蛋白 细菌；并利用这些细菌作为系统来研究 蛋白质生物合成、输出和释放的分子机制 集合。这些可溶的酶和蛋白质具有多种 有趣的氧化还原中心，包括黄素，铁硫中心， 血红素、铜和新的吡咯喹啉醌(PQQ) 辅因子；许多是可诱导的，合成到非常高的水平； 其中许多被输出到周质空间并在其中发挥作用 这些细菌。它们的结构和物理性质 氧化还原蛋白将被测定，而氧化还原蛋白的动力学 氧化还原蛋白之间的相互作用将按顺序发挥作用 分析过了。这将允许得出特定的推论和 关于结构-功能关系的测试 分子内和分子间电子的作用机制 运输。PQQ在甲胺催化中的作用 将对脱氢酶进行定义。这将具有广泛的意义 因为哺乳动物的含铜胺氧化酶，它 在调节生物胺水平方面起着重要作用， 还拥有PQQ。要研究的每一种氧化还原蛋白都是 代表普遍存在于 大自然。因此，结构和功能之间的类比 这些细菌蛋白和它们的真核对应蛋白将是 以物理、免疫学和动力学分析为特征。 体外翻译和易位系统将被开发成 研究这些基因表达的机制 呼吸蛋白受调节，前体蛋白受调节 加工过的假体基团附着在脱辅基蛋白上， 多亚单位酶被组装，多肽被 通过生物膜运输。此信息应为 极大地提高了我们对蛋白质生物发生的理解 参与能量转导和输出的 总体来说是蛋白质。因为能量新陈代谢对所有生物都至关重要 事情，建议的研究将与我们的理解相关 一个关键的生物过程。

The objective of this proposal is to define the kinetic mechanisms and physiological roles of a variety of oxidoreductases and electron carrier proteins found in methylotrophic and autotrophic bacteria; and to exploit these bacteria as systems for the study of the molecular mechanisms of protein biosynthesis, export, and assembly. These soluble enzymes and proteins possess a variety of interesting redox centers including flavins, iron-sulfur centers, hemes, copper, and the novel pyrroloquinoline quinone (PQQ) cofactor; many are inducible and synthesized to very high levels; and many are exported to and function in the periplasmic space of these bacteria. The structural and physical properties of these redox proteins will be determined and the kinetics of the interactions of redox proteins which function in sequence will be analyzed. This will allow specific inferences to be drawn and tested concerning structure-function relationships which pertain to the mechanisms of intramolecular and intermolecular electron transport. The role of PQQ in catalysis by methylamine dehydrogenase will be defined. This will have broad significance in that the mammalian copper-containing amine oxidases, which play an important role in regulating the levels of biogenic amines, also possess PQQ. Each of the redox proteins to be studied is representative of families of proteins which are ubiquitous in nature. As such, the structural and functional analogies between these bacterial proteins and their eukaryotic counterparts will be characterized by physical, immunological, and kinetic analyses. In vitro translation and translocation systems will be developed to study the mechanisms by which the expression of these respiratory proteins are regulated, precursor proteins are processed, prosthetic groups are attached to apoproteins, multisubunit enzymes are assembled, and polypeptides are transported across biological membranes. This information should greatly enhance our understanding of the biogenesis of proteins which are involved in energy transduction and of exported proteins in general. As energy metabolism is vital to all living things, the proposed studies will be relevant to our understanding of a critical biological process.