Siderophores as anchors in artificial metalloenzymes

该项目涉及开发人造金属酶，它由一个合成催化中心组成，该中心通过锚基连接到充当支架的蛋白质上。这种设计允许有机金属催化剂的化学反应能力与蛋白质的选择性和生物相容性相结合。这种人造酶将允许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，这种人工酶还可以用来激活抗生素。这个项目中要研究的锚基是基于铁载体的，铁载体是细菌产生的用于吸收必需铁的配体。形成的铁(III)-铁载体络合物非常稳定，并能积极地运输到细菌细胞中。在革兰氏阴性菌中，转运涉及通过特定的外膜受体识别和摄取，然后被周质结合蛋白捕获并输送到内膜转运体，然后转运到细胞质中。在人工酶中，作为新型蛋白质支架的是周质铁载体结合蛋白。这种方法的优点是通过铁载体摄取系统将合成的催化剂主动输送到细菌细胞中。一旦催化剂与铁铁载体络合物一起被带走，它们就会被它们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，在那里它们可用于催化转化或激活抗菌前药。通过这种方式，通过利用铁载体介导的细菌铁吸收途径，细菌细胞的新陈代谢被利用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.