Structure-function studies on protein homodimers

许多蛋白质成对发挥功能：两条相同的蛋白质链相互结合形成一个功能单位。 从某种意义上说，他们就像一对同卵双胞胎一起工作。 研究蛋白质如何工作的一种方法是通过定点诱变将变化引入蛋白质，这使得科学家能够指定蛋白质如何改变，然后研究这些变化如何影响蛋白质的功能。 当应用于具有两条相同链的蛋白质时，两条链都将被改变。研究这种只有一条链被改变的蛋白质，看看这是如何影响功能单位的，这将是很有趣的。再想想这对双胞胎，想象他们都是右撇子（毕竟，他们是一模一样的！）。定点突变可以改变它们的惯用手，所以它们都是左撇子。这种变化将如何影响他们的工作方式？ 如果你可以改变双胞胎中的一个的惯用手，这样你就可以看到当一个是左撇子，另一个是右撇子时，这对双胞胎是如何工作的？这就是我们实验室所做的：我们制备不再相同的二聚体对，并研究该对的性质。 由于所有已知蛋白质中有近一半是由这样的蛋白质对组成的，因此我们的工作具有普遍价值，尽管我们将自己限制在少数蛋白质上。

Many proteins function in pairs: two identical protein chains associate with each other to make a functional unit. In a sense, they are like a set of identical twins that work together. One way of investigating how proteins work is by introducing changes into them by site-directed mutagenesis, which allows a scientist to specify how the protein is changed, and then to study how those changes affect the function of the protein. When applied to proteins with two identical chains, both chains will be altered. It would be interesting to study such proteins in which only one chain is altered, to see how this affects the functional unit. Think of the twins again, and imagine that they are both right handed (after all, they are identical!). Site directed mutagenesis would allow you to change their handedness, so they are both left handed. How would this change affect how they work? What if you could change the handedness of just one of the twins, so that you could see how the pair works when one is left handed and the other is right-handed? This is what our laboratory does: we prepare dimer pairs that are no longer identical, and study the properties of the pair. As close to half of all known proteins consist of such pairs, our work is of general value, even though we restrict ourselves to just a handful of proteins.