Functional Analysis of Thiol-Disulfide Oxidoreductases in Streptococcus gordonii

二硫键是在两个氨基酸半胱氨酸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活性构象(形状)以执行适当的功能或活动。二硫键是通过称为硫醇-二硫代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是众所周知的。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。拟议的研究旨在了解以戈登链球菌为模式细菌的革兰氏阳性细菌是如何形成二硫键的。戈登氏链球菌是一种在人类口腔中发现的正常细菌，是牙菌斑的一部分。由于口腔环境的变化，从食物的消耗，唾液的流动，以及口腔的频繁运动，戈登氏链球菌发展了许多特征，成为一种成功的有机体。这些特征包括在牙齿上形成厚厚的一层菌斑并从环境中提取DNA的能力。与这些特征有关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化技术来剖析戈登氏链霉菌中二硫键形成的确切机制。因此，这项研究提供了对蛋白质折叠和功能的理解，这是细胞中生物过程的基础。

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.