The influence of metal fluorides on the structure and dynamics of phosphoryl transfer enzymes

生命系统依赖酶通过催化作用加速多种化学反应。其中最广泛的反应涉及在不同分子之间转移磷酸基团-磷酸转移反应在例如为细胞提供能量，合成和分解重要成分以及细胞内的通信系统中发挥核心作用。磷酸基团极难去除，因此高效的催化对于控制这些细胞过程至关重要。尽管模型研究已经教会了我们很多关于内在化学的知识，但我们对磷酸盐转移酶所提供的反应速率的巨大加速的起源-从比宇宙存在的时间更长到不到一秒-的理解还处于初级水平。理想情况下，我们会研究一种酶在催化临界点的快照，但这是无法实现的，因为这种物种的寿命太短了。因此，目前理解这种催化作用如何发生的框架取决于涉及化学物质的研究，这些化学物质看起来像催化临界点处存在的物质，但却将酶困在这种状态。我们已经发现磷酸转移酶能够在催化发生的位点组装氟化镁。氟化镁看起来更类似于被预测为催化速率的决定因素的物种，而不是任何其他尚未描述的物种，但在没有酶的情况下通常是不可观察的。这种酶利用其巨大的结合能力来稳定氟化镁。这为我们提供了强有力的证据，说明酶是如何催化磷酸盐转移反应的。我们将比较蛋白质在氟化镁存在下的结构和运动方面的行为与以前最知名的磷酸盐转移催化类似物氟化铝相比。镁物种的三角形形状比正方形铝物种更接近于转移的磷酸基团。我们还将调查以前报道的三角形铝物种是否实际上是镁物种，我们将研究氟化物与酶结合的不同方式。这些结论对其他磷酸转移酶具有广泛的适用性。理解这一过程对于设计用作治疗剂（药物）的酶抑制剂和使用酶的生物背景技术（例如生物修复）至关重要。这也将有助于从理论上理解重要的生物分子是如何工作的。

Living systems depend on enzymes to speed up a multitude of chemical reactions via catalysis. One of the most widespread reactions required involves the transfer of a phosphate group between different molecules - phosphate transfer reactions play a central role in, for example, providing energy to cells, the synthesis and breakdown of vital components, and communication systems within cells. Phosphate groups are extremely difficult to remove and so highly efficient catalysis is crucial for the control of these cellular processes. Although model studies have taught us much about the intrinsic chemistry required, our understanding of the origins of the enormous accelerations of reaction rates afforded by phophate transfer enzymes - from taking longer than the time for which the universe has been in existence to less than a second - are at a rudimentary level . Ideally, we would study a snapshot of an enzyme at the critical point of catalysis but this is unachievable since the lifetime of such species is too short. Hence, the current framework for understanding of how this catalysis occurs depends on studies involving chemicals that look like the species present at the critical point of catalysis but which trap the enzyme in this state. We have discovered that a phosphate transfer enzyme is capable of assembling magnesium fluoride in the site where catalysis occurs. Magnesium fluoride looks more similar to the species predicited to be the determinant of the catalytic rate than any other yet described, but is not normally observable in the absence of the enzyme. The enzyme is using its immense binding capabilities to stabilise magnesium fluoride. This provides us with strong evidence as to how the enzyme is catalysing the phosphate transfer reaction. We will compare how the protein behaves in terms of its structure and movement in the presence of magnesium fluoride compared with the previously best known analogue of phosphate transfer catalysis, aluminium fluoride. The triangular shape of the magnesium species fits far closer to the transfering phosphate group than the square aluminium species. We will also investigate whether previously reported triangular aluminium species are in fact magnesium species, and we will examine the different ways in which fluoride can bind to the enzyme. The conclusions should be broadly applicable to other phosphate transfer enzymes. An understanding of this process is vital to the design inhibitors of enzymes for use as therapeutic agents (drugs) and to technologies that use enzymes out of their biological context, for example bioremediation. It will also help the theoretical understanding of how important biological molecules work.