Investigations into the unprecedented reactions associated with the biosyntheses of hemes

该项目旨在对我们理解细菌中如何制造血红素和类似血红素的分子产生重大影响。在这样做时，这项研究将影响到BBSRC的几个重要优先领域，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，作为一种主要的生命色素，血红素至少有三条不同的合成路线。对这一应用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所涉及的转化涉及一些非常新颖的化学，如果重新设计，这些化学可以应用于工业生物技术。在这方面，研究计划涉及跨学科技术，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过程。我们以前的研究表明，血红素不是由单一的“经典”途径产生的，而是可以通过“替代”或“过渡”途径产生的。特别是，我们希望了解Hemy的作用，这是一种最近发现的共比例卟啉合成酶，它通过去除6个电子和6个质子来氧化铜卟啉原。通过对化学文库的具体搜索，我们已经发现了这种酶的一些抑制剂，但为了促进它们的发展，我们需要更多地了解这种酶的作用。类似地，已经确定了两种不同的酶，它们通过丙酸侧链的脱羧基转化为乙烯基团，将铁-共比例卟啉转化为血红素。当然，这种化学在将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大的工业意义。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为了了解D1血红素的合成，我们在分子水平上描述了不同的步骤，取得了巨大的进展。特别令人感兴趣的是Nirn的反应，它能够催化在周质范围内的丙酸侧链中引入双键，而不需要任何黄素或烟酰胺辅因子的辅助。同样，这种化学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式，为高价值和平台化学品减少烷烃。为了再次实现这一长期目标，我们需要确定反应的确切性质，然后重新设计系统，使其能够用于其他环境。总体而言，这项研究通过在分子水平上描绘事件的分子肖像，解决了与细胞内重要代谢物的生物合成有关的基本生化问题。通过这样做，它将提供对复杂生物合成途径进化的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方面的领先地位，并保持我们的组织在该领域作为世界领导者的地位。

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.