INTEGRATION OF F1 AND F0 ECTORS OF E. COLI PROTON-ATPASE

亚基“B”（也称为“uncF”蛋白）是蛋白质中的三个亚基之一。 E. coliProton-ATPase。 其氨基酸序列是已知的。 最近的数据表明，亚基B与F1区特异性结合（ ATP合成/水解催化单位）至Fo部门（ 膜中的质子通道）。 与预测一起， 可能是亚基B的二级和三级结构， 表明该亚基在F1的整合中起核心作用， 以及ATP水解与H+离子转运的耦合 （“能量耦合”）。 为了评估特定残基和结构域的重要性， 在F1-Fo整合中，亚基B将被多种 包括化学修饰、有限蛋白水解、局部化 诱变 功能相关性将通过分析影响 通过Fo的被动质子运输的亚基B修饰 特异性F1结合、ATP驱动质子泵送和 质子梯度诱导的F1构象变化。 交联 将进行实验以确定亚基的哪些残基或结构域 B与F1亚基结合，将对部分回复突变体进行检查。 作为揭示亚单位间相互作用的另一种方式进行 在质子-ATP酶的亚基B和其它亚基之间。 离子转运ATP酶中的“能量耦合”的性质是一种 生物学的基本问题。 通过关注亚基B，我们将推导出 对这一过程的深入研究。

Subunit "b" (also called "uncF" protein) is one of three subunits in the Fo-sector of E. coli proton-ATPase. Its amino acid sequence is known. Recent data implicates subunit b in specific binding of the F1-sector (the ATP synthesis/hydrolysis catalytic unit) to the Fo-sector (the proton-channel in the membrane). Taken together with predictions of the likely secondary and tertiary structure of subunit b, the evidence indicates that this subunit plays a central role in integration of the F1 and Fo sectors and in the coupling of ATP hydrolysis to H+ ion transport ("energy coupling"). In order to assess the importance of specific residues and domains of subunit b in F1-Fo integration, subunit b will be modified by a variety of techniques including chemical modification, limited proteolysis, localized mutagenesis. Functional correlations will be made by assaying the effects of the subunit b modifications on passive proton-transport through Fo specific F1-binding, ATP-driven proton-pumping and transmittal of proton-gradient-induced conformational changes to F1. Cross-linking experiments will be done to determine which residues or domains of subunit b bind to F1-subunits, and examination of partial revertants will be carried out as an alternative way of uncovering intersubunit interations between subunit b and other subunits of the proton-ATPase. The nature of "energy-coupling" in ion-transporting ATPases is a fundamental problem of biology. By focusing on subunit b we will deduce molecular insights into this process.