Synthesis of novel siderophores for the investigation of the pore size of transmembrane siderophore-receptors and development of siderophore conjugates for the diagnosis of infections with Gram-negative bacteria

合成新型铁载体用于研究跨膜铁载体受体的孔径，并开发铁载体缀合物用于诊断革兰氏阴性菌感染

• 批准号: 418299168
• 负责人: Professor Dr. Philipp Klahn
• 金额: --
• 依托单位: Institutionen för Kemi och Molekylärbiologi
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/418299168?language=en
• 关键词: Synthesis; novel; siderophores; investigation; pore

In the view of growing resistance of pathogenic, Gram-negative bacteria against established antibiotics, the development of novel antimicrobials and concepts to fight and detect pathogenic bacteria is of enormous importance. An innovative strategy for the development of novel antibiotics against Gram-negative bacteria is based on the conjugation of antimicrobial drugs to siderophores, small molecule iron-binders, known to be actively transported across the cell wall barrier of Gram-negative bacteria through recognition by specific siderophore receptors. Such Trojan Horse conjugates can actively deliver drugs or reporter molecules to bacteria and accumulate them inside. Especially, Enterobactin and Salmochelins, which are high affinity iron binders, playing an important role for iron accumulation during infection in human hosts, are in the focus of the development of novel siderophore conjugates. However, to date there is only limited information on the actual size of the transient pore of the transmembrane siderophore receptors opened after siderophore recognition. The present project aims of developing Enterobactin and Salmochelin derivatives bearing a novel attachment point for effector molecules in the backbone of the siderophores outside of the area important for recognition. Based on these siderophores novel stimuli-responsive siderophore-reporter conjugates for the detection of bacteria are planned to be synthesized. Therefore, novel latent fluorescent Rhodamin-based reporter molecules bearing an azo-reductase-responsive amino-trimethyl-lock-trigger should be developed, which are supposed to be activated upon siderophore-mediated uptake into bacteria by intracellular azo-reductases. Additionally, NIR-fluorescent indoheptacyanin-based reporter molecules with a para-nitrobenzyl-trigger are planned to be created, which are supposed to show a fluorescence shift to the red, visible wavelength upon reduction by intracellular nitro-reductases. Furthermore, based on the presented siderophores the development of conjugates with size-defined dummy payloads as well as stimuli-sensitive [2]-rotaxane-siderophore-reporter conjugates are envisaged, which for the first time should allow the investigation of the pores of siderophore receptors FepA and IroN concerning size, rigidity and polarity of potential conjugate payloads. The resulting data on structure-activity-relationships are planned to enable the design and development of antimicrobial siderophore-drug conjugates based on the presented siderophores for the treatment of infections with Gram-negative bacteria within a follow up grant application.

鉴于致病性革兰氏阴性菌对已建立的抗生素的耐药性不断增长，开发新的抗微生物剂和对抗和检测致病菌的概念具有巨大的重要性。用于开发针对革兰氏阴性菌的新型抗生素的创新策略是基于抗微生物药物与铁载体（小分子铁结合剂）的缀合，已知铁载体通过特异性铁载体受体的识别而主动转运穿过革兰氏阴性菌的细胞壁屏障。这种特洛伊木马结合物可以主动将药物或报告分子传递给细菌并在细菌内部积累。特别是肠杆菌素和Salmochelins，它们是高亲和力的铁结合剂，在人类宿主感染期间对铁积累起重要作用，是新型铁载体缀合物开发的焦点。然而，到目前为止，只有有限的信息，铁载体识别后打开的跨膜铁载体受体的瞬时孔的实际大小。本项目的目的是开发肠杆菌素和Salmochelin衍生物，其具有在铁载体的骨架中对识别重要的区域之外的效应分子的新型附着点。基于这些铁载体的新的刺激响应铁载体报告共轭物的细菌检测计划被合成。因此，新型潜在的荧光罗丹明为基础的报告分子承载的偶氮还原酶响应的氨基三甲基锁触发器，这是应该被激活后铁载体介导的摄取到细菌细胞内的偶氮还原酶。此外，计划创建具有对硝基苄基触发剂的基于NIR荧光indoheptacyanin的报告分子，其被认为在通过细胞内硝基还原酶还原时显示荧光向红色可见波长偏移。此外，基于所提出的铁载体，设想了具有尺寸限定的虚拟有效载荷以及刺激敏感的[2]-轮烷-铁载体-报告缀合物的缀合物的开发，这将首次允许研究铁载体受体FepA和IroN的孔，涉及潜在缀合物有效载荷的尺寸、刚度和极性。所得到的关于结构-活性-关系的数据计划用于在后续资助申请中基于所提出的用于治疗革兰氏阴性菌感染的铁载体设计和开发抗微生物铁载体-药物缀合物。