8TTI

Trp-6-Halogenase BorH complexed with FAD and Trp

8TTI の概要

• エントリーDOI: 10.2210/pdb8tti/pdb
• 分子名称: Tryptophan 6-halogenase, TRYPTOPHAN, SULFATE ION, ... (5 entities in total)
• 機能のキーワード: halogenase, oxidoreductase, flavoprotein
• 由来する生物種: uncultured bacterium
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 244036.70

構造登録者

Lingkon, K.,Bellizzi, J.J. (登録日: 2023-08-14, 公開日: 2023-08-30, 最終更新日: 2025-07-23)

主引用文献

Ashaduzzaman, M.,Lingkon, K.,De Silva, A.J.,Bellizzi 3rd, J.J.
Crystallographic and Thermodynamic Evidence of Negative Coupling in the Flavin-Dependent Tryptophan Halogenases AbeH and BorH.
Acs Omega, 10:5849-5865, 2025

PubMed Abstract: Flavin-dependent halogenases (FDHs) regioselectively halogenate aromatic substrates using halide ions, O, and reduced flavin (FADH) at physiological temperatures in aqueous solution, making them a green alternative to conventional synthetic methods for aryl halide preparation. To better understand mechanistic details that limit FDH catalytic efficiency and potentially hinder their application as biocatalysts, we investigated the halogenation activity, substrate scope, crystal structures, and ligand binding of the Trp-5-halogenase AbeH and the Trp-6-halogenase BorH. Partitioning of FAD and Trp into different subunits of BorH crystals and an inability to incorporate Trp into AbeH/FAD crystals suggested that binding of flavin and Trp are negatively coupled in both proteins. Isothermal titration calorimetry and fluorescence quenching experiments confirmed that both AbeH and BorH formed binary complexes with FAD or Trp, but Trp could not form ternary complexes with preincubated AbeH/FAD or BorH/FAD complexes. FAD could not bind to BorH/Trp complexes, but FAD appears to displace Trp from AbeH/Trp complexes in an endothermic entropically driven process. Observation of negative coupling in halogenases from two different clades with topological differences in their substrate binding sites suggests that this property and the limitations it places on catalytic efficiency may be a general characteristic of the FDH family.

PubMed: 39989782
DOI: 10.1021/acsomega.4c09590

実験手法

X-RAY DIFFRACTION (1.98 Å)