Investigations into the unprecedented reactions associated with the biosyntheses of hemes

该项目旨在对我们对细菌中血红素和类血红素分子如何形成的理解产生重大影响。这样做的研究将影响到BBSRC的几个重要的优先领域，包括抗菌素耐药性和工业生物技术的战略方法。这是因为在我们之前的研究过程中，我们发现血红素，一种主要的生命色素，是通过至少三种不同的途径合成的。该应用程序的研究突出了可用于通过利用这些生化差异来支持新型抗菌剂开发的策略。此外，这些血红素的生物合成过程中所涉及的转化涉及到一些非常新颖的化学物质，如果重新设计，这些化学物质可以应用于工业生物技术。在这方面，研究方案涉及跨学科技术，有可能通过开发新的生物催化实体和途径将基本发现转化为新的产品和工艺。我们之前的研究表明，血红素不是通过单一的“经典”途径产生的，而是通过“替代”或“过渡”途径产生的。我们特别想看看HemY的作用，HemY是一种最近发现的卟啉合成酶，它通过去除6个电子和6个质子来氧化卟啉原。通过对化学文库的特定搜索，我们已经确定了一些这种酶的抑制剂，但为了加强它们的开发，我们需要更多地了解这种酶的作用。类似地，已经确定了两种单独的酶，通过丙酸侧链脱羧成乙烯基，将Fe-coproporphyrin转化为血红素。当然，这种化学在脂肪酸转化为烯烃的生物技术中非常重要，因此为脂肪酸底物重新设计这些酶将具有重要的工业意义。然而，要做到这一点，我们必须首先了解驱动底物识别、特异性和催化机制的分子过程。研究的最后一部分是针对d1血红素合成的理解，我们在分子水平上描绘各个步骤方面取得了巨大进展。特别令人感兴趣的是NirN的反应，它能够在外周质范围内催化将双键引入丙酸侧链，而不需要任何黄素或烟酰胺辅助因子的帮助。同样，这种化学反应将引起生物技术部门的广泛兴趣，特别是作为一种潜在的廉价方法，可以减少高价值和平台化学品的烷烃。为了实现这一长期目标，我们需要确定反应的确切性质，然后重新设计系统，使其能够在其他情况下使用。总的来说，该研究通过在分子水平上描绘事件的分子肖像，解决了有关细胞内重要代谢物生物合成的基本生化问题。这样一来，它将为复杂生物合成途径的进化提供新达尔文主义的理解。它还将有助于保持英国在生物分子科学研究的前沿地位，并保持我们的团队在该领域的世界领先地位。

The project aims to have a major impact on our understanding of how heme and heme-like molecules are made within bacteria. In so doing the research will impinge upon several important priority areas of BBSRC, including antimicrobial resistance and strategic approaches to industrial biotechnology. This is because in the course of our previous research we have discovered that heme, a major life pigment, is synthesized by at least three distinct routes. The research in this application highlights strategies that can be used to underpin the development of novel antimicrobials through the exploitation of these biochemical differences. Moreover, the transformations involved in the biosyntheses of these hemes involve some very novel chemistry, which if redesigned could be applied to industrial biotechnology. In this respect the research programme involves cross-disciplinary technologies, with the potential to permit the translation of basic discoveries into new products and processes through the development of new biocatalytic entities and pathways.Our previous research has demonstrated that heme is not made by a single "classic" pathway, rather it can be made either by an "alternative" or a "transitional" pathway. In particular we wish to look at the role of HemY, a recently identified coproporphyrin synthase, that oxidises coprporphyrinogen through the removal of 6 electrons and 6 protons. We have identified a number of inhibitors of this enzyme through specific searches of chemical libraries, but to enhance their development we need to know more about the action of the enzyme. Similarly, two separate enzymes have been identified that convert Fe-coproporphyrin into heme through the decarboxylation of propionic acid side chains into vinyl groups. Such chemistry is, of course, very significant in biotechnology for the conversion of fatty acids into alkenes and thus redesigning these enzyme for fatty acid substrates would have significant industrial relevance. However, to achieve this we must first understand the molecular processes that drive substrate recognition, specificity and catalytic mechanism. The final part of the research is tailored towards an understanding of d1 heme synthesis, where we have make huge progress in delineating the various steps at the molecular level. Of particular interest is the reaction of NirN, which is able to catalyse the introduction of a double bond into one of the propionate side chains within the confines of the periplasm and without the assistance of any flavin or nicotinamide cofactors. Again such chemistry would be of broad interest to the biotechnology sector, especially as a potentially cheap way of reducing alkanes for high-value and platform chemicals. To achieve this long-term goal again we need to determine the precise nature of the reaction and then redesign the system to allow it to be used in other contexts.Overall, the research addresses basic biochemical questions concerning the biosynthesis of important metabolites within the cell by painting a molecular portrait of events at the molecular level. In so doing it will provide a neodarwinistic understanding of the evolution ofcomplex biosynthetic pathways. It will also help maintain the UK at the cutting edge of biomolecular science research and maintain the position our groups have as world leaders in this field.