Probing the mechanism of the Tat protein transport system at the single complex level in whole bacterial cells

一些细菌蛋白质在细胞外部起作用，例如细菌病原体产生的毒素。由于所有的蛋白质都是在细菌内部制造的，因此胞外蛋白质必须穿过通常不可渗透的细胞膜移出细胞。这一任务是由位于细胞膜上的蛋白质转运蛋白完成的。一种类型的转运蛋白移动未折叠的蛋白质，将它们穿过细胞膜，就像穿过针眼的线一样。相比之下，第二种类型的转运蛋白，我们称之为达特系统，将折叠的蛋白质跨膜移动。在这个项目中，我们希望增加我们对达特系统如何工作的理解。我们在参与达特途径的各种蛋白质上添加了标记，使它们在特殊类型的显微镜下看起来像彩色斑点。我们甚至可以看到整个细菌细胞中的斑点。通过研究斑点的行为，我们可以了解达特成分在活细胞中的功能。达特系统是一个可能的药物靶点，因为它是细菌致病所必需的，但在人类中没有发现。它也具有生物技术的意义，因为它可以用来分泌有用的蛋白质产品。

Some bacterial proteins operate on the outside of the cell, for example the toxins produced by bacterial pathogens. Since all proteins are made inside the bacterium the extracellular proteins must be moved out of the cell across the normally impermeable cell membrane. This task is carried out by machines termed protein transporters that are located in the cell membrane. One type of transporter moves unfolded proteins, threading them across the membrane like string through the eye of a needle. By contrast, a second type of transporter, which we term the Tat system, moves folded proteins across the membrane. In this project we want to increase our understanding of how the Tat system works. We have added labels to the various proteins involved in the Tat pathway which make them appear as coloured spots when viewed in a special type of microscope. We can even see the spots in whole bacterial cells. By studying the behaviour of the spots we can learn about how the Tat components function in living cells. The Tat system is a possible drug target because it is required for bacterial pathogenesis but is not found in humans. It is also of biotechnological interest because it could be used to secrete useful protein products.