Mechanismus der Thioloxidase Mia40

最近，在线粒体的膜间隙中发现了二硫键结合的蛋白质，并且发现了介导这些蛋白质的氧化折叠的二硫键中继系统。该系统的关键组分Mia 40和Erv 1对酵母的生存力至关重要。它们在体内和体外功能的基本原理是已知的，Mia 40和几种底物蛋白的晶体和NMR结构是可用的。我们的目标是在分子水平上阐明Mia 40/Erv 1介导的氧化折叠的动力学机制。我们将研究Mia 40如何催化底物蛋白中硫醇-二硫键交换反应的各个步骤，构象折叠和Mia 40介导的二硫键形成如何耦合，Mia 40的动力学如何受到其辅因子Erv 1和Hot 13的影响，特别是，Mia 40的酶促机制与催化内质网和细菌周质中氧化折叠的巯基二硫键交换酶有何不同。我们希望这些研究不仅有助于理解线粒体中这种新发现的折叠系统的分子机制，而且还为理解催化氧化折叠的基本分子机制提供了一个很好的途径。

Recently, disulfide-bonded proteins were found in the inter-membrane space of mitochondria, and a disulfide relay system was discovered that mediates the oxidative folding of these proteins. The key components of this system, Mia40 and Erv1 are essential for viability of yeast. The basic principles of their function in vivo and in vitro are known, and crystal and NMR structures of Mia40 and several substrate proteins are available. It is our aim to elucidate the kinetic mechanism of Mia40/Erv1- mediated oxidative folding at the molecular level. We will examine how Mia40 catalyzes the individual steps of thiol-disulfide exchange reactions in the substrate proteins, how conformational folding and Mia40-mediated disulfide bond formation are coupled, how the kinetics of Mia40 are affected by its co-factors Erv1 and Hot13, and, in particular, how Mia40 differs in its enzymatic mechanism from the thioldisulfide exchange enzymes that catalyze oxidative folding in the endoplasmic reticulum and in the bacterial periplasm. We expect that these studies will be helpful not only to understand the molecular mechanism of this newly discovered folding system in the mitochondria, but that it also provides a good access to understanding the basic molecular mechanisms of catalyzed oxidative folding.