Catechol siderophore

Catechol siderophores, such as enterobactin, azotochelin, and protochelin, are high-affinity iron-chelating molecules secreted by bacteria to acquire essential ferric iron from their environment [1]. Enterobactin, produced by enteric bacteria like Escherichia coli, is one of the most potent natural chelators known, enabling pathogens to thrive in iron-limited host environments [2]. These molecules are critical virulence factors, as they allow bacteria to subvert host nutritional immunity by stripping iron from proteins like transferrin [3]. The human protein Lipocalin-2 (Siderocalin) serves as a key innate immune defense by binding and sequestering these catecholate siderophores to prevent bacterial utilization [4]. In pharmacology, these structures are exploited via the 'Trojan horse' strategy, where antibiotics are conjugated to catechol groups to facilitate active transport into bacteria through TonB-dependent receptors like FepA [5]. Cefiderocol is the first FDA-approved antibiotic to utilize this mechanism, effectively bypassing common resistance pathways in multi-drug resistant Gram-negative pathogens [6]. Beyond their role in iron acquisition, research into inhibiting the enzymes involved in their biosynthesis, such as the EntA-E pathway, offers a potential strategy for developing new narrow-spectrum antibacterials [2]. Additionally, the emergence of 'stealth' siderophores like salmochelin, which evade Lipocalin-2 binding, highlights the ongoing evolutionary battle between host and pathogen [3].

Other names

EnterobactinAzotochelinProtochelinEnterochelin2,3-Dihydroxybenzoylserine siderophoresCatecholate siderophoresEnterobactin, azotochelin, protochelin and related catechol siderophores

Siderophore-mediated active transport (Trojan horse mechanism) via TonB-dependent receptors and sequestration by host innate immune proteins like Lipocalin-2.