Mechanistic investigations into the novel monooxygenases CobG and CobZ involved in vitamin B12 biosynthesis

维生素是人类完成饮食所需的基本营养素，从定义上讲，它不是在自己的身体里制造的。维生素B12新陈代谢最有趣的方面之一是，这种重要的营养物质只由细菌/没有更高级的生物(真核生物)有能力制造这种化合物。虽然一些真核生物保留了维生素B12在其新陈代谢中的作用，但其他生物，如植物，已经进化成没有B12的生命。其结果是，那些严格素食的人容易缺乏维生素B12-这种状态与一系列症状有关，包括巨幼细胞性贫血、神经障碍和未出生婴儿的发育问题。维生素B12缺乏也是老年人的一个问题，增加饮食中的B12水平可以缓解症状。因此，有充分的医学理由来了解这种维生素是如何产生的，以便我们能够设计出制造更多维生素的方法，从而提高饮食中维生素B12的水平。在这一应用中，我们希望探索维生素B12生物合成的一个重要阶段。维生素B12是由一家酶工厂制造的/事实上，大约需要30种不同的酶才能制造这种重要的化合物。酶是生物催化剂，可以加速在细胞内进行的反应/如果没有酶，许多反应需要十多年的时间才能发生，而不是几秒钟。与所有酶一样，负责维生素B12生物合成的酶表现出特异性。这意味着维生素B12生物合成途径中的每个酶只催化一个反应/它只对该反应是特异的。这就引出了这样一个问题：这么大的通道是如何出现的？一种当前的理论是，有些酶是适应性的，也就是说，它们催化一般的反应，只是后来变得高度特异。我们已经确定了维生素B12生物合成的一个步骤，似乎获得了两个完全不同的酶来催化一个反应。我们希望研究这两种酶的作用，以了解它们如何适应维生素B12的生物合成途径。这一应用旨在增加我们对生化途径如何运作、如何控制它们以及如何设计它们以增强宿主细胞的代谢能力的理解。从医疗、工业和财富创造战略的角度来看，这项研究计划紧跟BBSRC的职权范围和抱负。

Vitamins are essential nutrients required by humans to complete their diet, and by definition are not made within their own body. One of the most interesting aspects of vitamin B12 metabolism is that this essential nutrient is made only by bacteria / no higher order organism (eukaryote) has the ability to make this compound. Whilst some eukaryotes have retained a role for vitamin B12 in their metabolism, others such as plants have evolved into a life without B12. A consequence of this is that those on strictly vegetarian diets are prone to vitamin B12 deficiency - a state that is associated with a wide range of symptoms including megablastic anaemia, neurological disorders, and developmental problems in unborn babies. Vitamin B12 deficiency is also a problem in the elderly, where an increase in the level of B12 in the diet can alleviate the symptoms. There are thus strong medical reasons for understanding how this vitamin is made so that we can devise ways to make more and thus increase the levels of vitamin B12 in the diet. In this application we wish to explore one important stage in the biosynthesis of vitamin B12. Vitamin B12 is made by a factory of enzymes / in fact it takes about thirty different enzymes to make this essential compound. Enzymes are biological catalysts that speed up reactions that go on inside cells / without enzymes many reactions would take over a decade to occur instead of just a few seconds. In common with all enzymes, the enzymes responsible for the biosynthesis of vitamin B12 show specificity. This means that each enzyme in the vitamin B12 biosynthetic pathway only catalyses one reaction / it is specific for that reaction only. This then leads to the question of how such large pathways may have arisen? One current theory is that some enzymes are adaptable / that is they catalyse general reactions and only become highly specific later on. We have identified one step in the biosynthesis of vitamin B12 that seems to have acquired two quite distinct enzymes to catalyse one reaction. We wish to study the action of these two enzymes in order to understand how they have adapted to the vitamin B12 biosynthetic pathway. This application is aimed at increasing our understanding of how biochemical pathways operate, how they are controlled and how they can be engineered to enhance the metabolic ability of the host cell. From medical, industrial and wealth creation strategic standpoints, this research programme closely follows the remit and aspirations of the BBSRC.