Synthetic biology approaches to construct metal analogues of vitamin B12 to act as anti-microbial and imaging agents for health applications.

维生素B12（钴胺素）是一种必需的微量营养素，其合成仅限于某些细菌。它是自然界中发现的最复杂的分子之一，由一个含钴的咕啉环和一个通过核苷酸环连接的较低碱基组成。钴胺素分子的生物活性取决于其中心金属离子的性质，我们已经成功地制备了几种钴胺素的金属类似物（Rh，Zn和Ni）。这是使用一种新的方法实现的，该方法由一种工程菌株组成，该菌株可以产生一种不含金属的中间体氢比酸（Hby），然后进行后续的生化和化学步骤以完成合成并产生所需的类似物。虽然该系统运行良好，但我们希望通过进一步工程化E.我们已经确定铑类似物是B12依赖性过程的抑制剂，但我们目前对金属类似物的生物活性知之甚少。我们希望通过观察类似物的细胞摄取和运输，它们对B12依赖性酶和过程的影响，并记录存在的任何抗菌/抗癌活性，来扩展我们在这一领域的知识。取代金属离子的能力也打开了创造独特的正电子发射断层扫描（PET）医学成像剂的可能性，可用于癌症诊断。合成一系列钴胺素的金属类似物（Cu，Rh，Zn和Ni）.研究金属类似物的生物学特性（例如，维生素摄取/转运、酶抑制、抗微生物剂/抗癌剂）。工程师E。一种能够生产无钴钴胺素（氢钴胺素）的大肠杆菌菌株。

Vitamin B12 (cobalamin) is an essential micronutrient whose synthesis is restricted to only certain bacteria. It is one of the most complex molecules found in Nature, consisting of a cobalt-containing corrin ring and a lower base attached via the nucleotide loop. The biological activity of the molecule is dependent on the properties of the metal ion at its centre.We have successfully prepared several metal analogues of cobalamin (Rh, Zn and Ni). This was achieved using a novel approach consisting of an engineered bacterial strain which can produce a metal-free intermediate, hydrogenobyric acid (Hby), and then subsequent biochemical and chemical steps to complete the synthesis and produce the desired analogues. While the system works well, we are looking to optomise/simplify the synthesis by further engineering the E. coli strain, using genes from Chromatium vinosum which is known to produce cobalt-free cobalamin under specific conditions.We have determined that the rhodium analogue is an inhibitor of B12-dependent processes, but we currently know very little about the biological activity of the metal analogues. We wish to expand our knowledge in this area by looking at the cellular uptake and trafficking of the analogues, their effect on B12-dependent enzymes and processes, and document any antimicrobial/anticancer activity present. The ability to replace the metal ion also opens the possibility of creating unique medical imaging agents for positron emission tomography (PET) which could be used in cancer diagnosis.The aim of this project is to:1. Synthesise a range of metal analogues of cobalamin (Cu, Rh, Zn and Ni).2. Investigate the biological properties of the metal analogues (eg. vitamin uptake/transport, enzyme inhibition, antimicrobial/anticancer agents).3. Engineer an E. coli strain capable of producing cobalt-free cobalamin (hydrogenobalamin).