8TE9

Crystal Structure of an Isethionate bound Substrate Binding Protein (IseP) from an Isethionate TRAP Transporter

8TE9 の概要

• エントリーDOI: 10.2210/pdb8te9/pdb
• 分子名称: Isethionate-binding periplasmic protein DctP, 2-hydroxyethylsulfonic acid, NITRATE ION, ... (5 entities in total)
• 機能のキーワード: trap transporter, substrate binding protein, isethionate, transport protein
• 由来する生物種: Oleidesulfovibrio alaskensis G20
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 75385.95

構造登録者

Newton-Vesty, M.C.,Dobson, R.C.J. (登録日: 2023-07-05, 公開日: 2024-07-10, 最終更新日: 2025-01-15)

主引用文献

Newton-Vesty, M.C.,Currie, M.J.,Davies, J.S.,Panjikar, S.,Sethi, A.,Whitten, A.E.,Tillett, Z.D.,Wood, D.M.,Wright, J.D.,Love, M.J.,Allison, T.M.,Jamieson, S.A.,Mace, P.D.,North, R.A.,Dobson, R.C.J.
On the function of TRAP substrate-binding proteins: the isethionate-specific binding protein IseP.
Biochem.J., 481:1901-1920, 2024

PubMed Abstract: Bacteria evolve mechanisms to compete for limited resources and survive in new niches. Here we study the mechanism of isethionate import from the sulfate-reducing bacterium Oleidesulfovibrio alaskensis. The catabolism of isethionate by Desulfovibrio species has been implicated in human disease, due to hydrogen sulfide production, and has potential for industrial applications. O. alaskensis employs a tripartite ATP-independent periplasmic (TRAP) transporter (OaIsePQM) to import isethionate, which relies on the substrate-binding protein (OaIseP) to scavenge isethionate and deliver it to the membrane transporter component (OaIseQM) for import into the cell. We determined the binding affinity of isethionate to OaIseP by isothermal titration calorimetry, KD = 0.95 µM (68% CI = 0.6-1.4 µM), which is weaker compared with other TRAP substrate-binding proteins. The X-ray crystal structures of OaIseP in the ligand-free and isethionate-bound forms were obtained and showed that in the presence of isethionate, OaIseP adopts a closed conformation whereby two domains of the protein fold over the substrate. We serendipitously discovered two crystal forms with sulfonate-containing buffers (HEPES and MES) bound in the isethionate-binding site. However, these do not evoke domain closure, presumably because of the larger ligand size. Together, our data elucidate the molecular details of how a TRAP substrate-binding protein binds a sulfonate-containing substrate, rather than a typical carboxylate-containing substrate. These results may inform future antibiotic development to target TRAP transporters and provide insights into protein engineering of TRAP transporter substrate-binding proteins.

PubMed: 39560287
DOI: 10.1042/BCJ20240540

実験手法

X-RAY DIFFRACTION (1.25 Å)