Structure-Guided Engineering of 2-Oxoglutarate-Dependent Oxygenases: Principles, Case Studies, and Emerging Opportunities

2-Oxoglutarate-dependent non-heme iron oxygenases (2OGX) catalyze a broad spectrum of oxidative transformations, including hydroxylation, halogenation, desaturation, cyclization, rearrangement, and endoperoxidation, through a conserved HxD/E…H facial triad and Fe(IV)=O chemistry. Their functional diversity arises from structural elements that define the catalytic pocket. Substrate-binding architectures can be categorized into four recurrent motifs-the conserved lip (CLip), conserved lid (CLid), specific lid (SL), and dimer lid (DL)-together with the major β-sheet framework (βI-βVI); mutations in these lid/lip elements and within β-strands collectively govern substrate entry, positioning, and radical partitioning. This review discusses representative case studies organized by reaction class-hydroxylation/halogenation, cyclization/rearrangement, endoperoxidation, and free amino acid oxidation-to illustrate how targeted substitutions in these motifs enable rational reprogramming of reactivity. Examples include hydroxylases converted to halogenases, fungal enzymes redirected to construct alternative meroterpenoid scaffolds, endoperoxidases generating non-natural products, and amino acid hydroxylases engineered for halogenation, desaturation, or aziridination. These studies highlight the structural plasticity of 2OGX scaffolds and establish them as programmable biocatalysts, with advances in structural biology and computational design expected to accelerate their application in synthetic biology, natural product discovery, and drug development. The literature published from 2015 through September 2025 is reviewed.