Siderophores as anchors in artificial metalloenzymes

该项目涉及人工金属酶的开发，该酶由合成催化中心组成，该催化中心通过锚基团连接到作为支架的蛋白质上。这种设计将有机金属催化剂的化学反应性与蛋白质的选择性和生物相容性结合起来。这种人工酶将使现有的催化过程在温和的条件下运行，并使新的生物技术转化成为可能。此外，这种人工酶还可用于激活抗生素。本项目中要研究的锚基团是基于铁载体的，铁载体是由细菌产生的用于摄取必需铁的配体。形成的铁(III)-铁载体复合物非常稳定，并主动运输到细菌细胞中。在革兰氏阴性菌中，转运包括通过特定的外膜受体进行识别和摄取，随后被周围质结合蛋白捕获，并传递到内膜转运蛋白转运到细胞质中。质周铁载体结合蛋白将作为新型的蛋白支架在人工酶中得到探索。这种方法的优点是通过铁载体摄取系统将合成催化剂主动运输到细菌细胞中。一旦催化剂与铁铁载体复合物一起被吸收，它们就会被各自的结合蛋白捕获。因此，目标人工酶自组装并在细菌细胞的周质中积累，在那里它们可能用于催化转化或抗菌前药的激活。通过这种方式，利用由铁载体介导的细菌铁摄取途径，利用细菌细胞的代谢来支持体内的化学转化。

The project involves the development of artificial metalloenzymes that consist of a synthetic catalytic centre that is linked via an anchor group to a protein that acts as a scaffold. This design allows the combination of the chemical reactivity of organometallic catalysts with the selectivity and biocompatibility of proteins. Such artificial enzymes would allow existing catalytic processes to run under mild conditions and make new biotechnological transformations possible. In addition, such artificial enzymes could be used to activate antibiotics.The anchor groups to be investigated in this project are based on siderophores, which are ligands that are produced by bacteria for the uptake of essential iron. The iron(III)-siderophore complexes formed are extremely stable and actively transported into the bacterial cell. In Gram-negative bacteria, transport involves recognition and uptake via a specific outer membrane receptor, followed by capture by a periplasmic binding protein and delivery to an inner membrane transporter for translocation into the cytoplasm. It is the periplasmic siderophore binding proteins that will be explored as novel protein scaffolds in artificial enzymes. The advantage of this approach is the active transport of the synthetic catalysts into the bacterial cell via the siderophore uptake system. Once the catalysts are taken-up along with the iron siderophore complexes, they are captured by their respective binding proteins. Hence the target artificial enzymes self-assemble and accumulate in the periplasm of the bacterial cell, where they may be used for catalytic transformations or the activation of antimicrobial prodrugs. In this way, by taking advantage of the bacterial iron-uptake pathway that is mediated by siderophores, the metabolism of the bacterial cell is exploited to support chemical transformations in vivo.