Functional Analysis of Thiol-Disulfide Oxidoreductases in Streptococcus gordonii

二硫键是在氨基酸半胱氨酸的两个分子之间形成的稳定键。二硫键的形成对蛋白质的稳定性至关重要，因为它们允许蛋白质折叠成一个活跃的构象（形状）来执行适当的功能或活动。二硫键是通过一种叫做硫-二硫氧化还原酶的酶的作用形成的。在革兰氏阴性菌中，二硫化物的形成途径已被很好地理解。相比之下，人们对革兰氏阳性细菌中二硫键是如何形成的知之甚少。提出的研究旨在了解二硫键是如何在革兰氏阳性细菌中形成的，使用戈多氏链球菌作为模型细菌。戈氏沙门氏菌是人类口腔中作为牙菌斑的一部分发现的一种正常细菌。由于食物的消耗、唾液的流动和口腔的频繁运动等口腔环境的变化，gordonii已经发展出许多特征，成为一个成功的生物。这些特征包括在牙齿上形成厚厚的牙菌斑和从环境中获取DNA的能力。参与这些特征的蛋白质含有二硫键，我们的目标是确定在这些蛋白质中负责形成二硫键的酶。我们将使用现代分子和生物化学技术来剖析二硫键如何在S. gordonii中形成的确切机制。因此，这项研究提供了对蛋白质折叠和功能的理解，这是细胞生物过程的基础。

A disulfide bond is a stable bond formed between two molecules of the amino acid cysteine. The formation of disulfide bonds is critical to the stability of the proteins because they allow the proteins to fold into an active conformation (shape) to carry out proper functions or activities. A disulfide bond is formed through the action of enzymes called thiol-disulfide oxidoreductases. In Gram-negative bacteria, the disulfide formation pathway is well understood. In contrast, very little is known about how disulfide bonds are formed in Gram-positive bacteria. The proposed research is designed to understand how disulfide bonds are formed in Gram-positive bacteria using Streptococcus gordonii as a model bacterium. S. gordonii is a normal bacterium found in the human mouth as part of the dental plaque. Because of the changing environment in the mouth from food consumption, saliva flow, and frequent movement of the mouth, S. gordonii has developed many traits to become a successful organism. These traits include the ability to form thick layer of plaque on teeth and pick up DNA from the environment. Proteins involved in these traits contain disulfide bonds and it is our goals to identify the enzymes responsible for forming disulfide bonds in these proteins. We will use modern molecular and biochemical techniques to dissect the exact mechanisms of how disulfide bonds are formed in S. gordonii. Thus, the research provides understanding to protein folding and function that is fundamental to biological processes in a cell.