Interactions and Reactions of Carbohydrates and Proteins

参与糖苷键(糖苷酶)水解的酶发挥着一系列重要的生物学作用，从消化过程中淀粉和纤维素等多糖的降解到单个细胞相互作用和与环境相互作用所需的糖蛋白的精挑细选的“修剪”。详细了解这些高效催化剂(它们将反应加速数十亿倍)是如何工作的，这不仅对于理解催化本身，设计这些酶来进行新的反应，而且对于设计和合成特定的抑制剂来控制细胞过程，从而可能作为治疗药物，都是有价值的。这项建议包括三个部分。在第一部分中，我们提议进行机制研究，以揭开我们一直在从病原体的一种酶中研究的一种新机制的细节：这可能导致抑制剂来控制感染。我们还提出了详细的机理研究，以了解酶如何如此有效地催化反应，以及它们如何控制其最适pH。在第二部分中，受到大自然母亲如何制造糖模拟物的最新发现的启发，我们提议探索其他类别的酶是否可以进行类似的反应。最后，我们提出了一种方法，用廉价的原料“重新训练”糖基转移酶，这种酶可以制造有用的糖衍生物。要做到这一点，我们应该利用遗传学、微生物学、细胞生物学以及分析和有机化学的工具，这一过程被称为“定向进化”。这可能导致糖基疗法和其他产品的制造战略得到改善。

The enzymes involved in the hydrolysis of glycosidic bonds (glycosidases) play a range of important biological roles, ranging from the degradation of polysaccharides such as starch and cellulose in digestive processes to the exquisitely selective 'trimming' of glycoproteins required for individual cells to interact with each other and with their environment. A detailed understanding of how these highly efficient catalysts (they accelerate reactions some billion-billion fold) work is valuable, not only in understanding catalysis itself, and engineering these enzymes to carry out novel reactions, but also in the design and synthesis of specific inhibitors to control cellular processes, thus possibly as therapeutics. This proposal comprises three parts. In the first part we propose mechanistic studies to unravel details of a novel mechanism that we have been studying from an enzyme from a pathogenic bacterium: this could lead to inhibitors to control infection. We also propose detailed mechanistic studies to understand how enzymes catalyze reactions so effectively and how they control their pH optima. In the second part, triggered by recent findings of how Mother Nature makes sugar mimetics, we propose to explore whether other classes of enzyme can carry out similar reactions. Finally we propose a methodology to "retrain" glycosyltransferases, enzymes that make useful sugar derivatives, to do so using inexpensive starting materials. To do this we shall harness the tools of genetics, microbiology, cell biology and analytical and organic chemistry in a process known as "directed evolution". This could lead to improved manufacturing strategies for sugar-based therapeutics and other products.