6S4Q

scdSav(SASK) - Engineering Single-Chain Dimeric Streptavidin as Host for Artificial Metalloenzymes

6S4Q の概要

• エントリーDOI: 10.2210/pdb6s4q/pdb
• 分子名称: Streptavidin, {N-(4-{[2-(amino-kappaN)ethyl]sulfamoyl-kappaN}phenyl)-5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanamide}(chloro)[(1,2,3,4,5-eta)-1,2,3,4,5-pentamethylcyclopentadienyl]iridium(III), GLYCEROL, ... (4 entities in total)
• 機能のキーワード: biotin-binding protein, artificial transfer hydrogenase, beta barrel, streptavidin, transport protein
• 由来する生物種: Streptomyces avidinii; 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 73591.89

構造登録者

Rebelein, J.G. (登録日: 2019-06-28, 公開日: 2019-09-25, 最終更新日: 2024-10-16)

主引用文献

Wu, S.,Zhou, Y.,Rebelein, J.G.,Kuhn, M.,Mallin, H.,Zhao, J.,Igareta, N.V.,Ward, T.R.
Breaking Symmetry: Engineering Single-Chain Dimeric Streptavidin as Host for Artificial Metalloenzymes.
J.Am.Chem.Soc., 141:15869-15878, 2019

PubMed Abstract: The biotin-streptavidin technology has been extensively exploited to engineer artificial metalloenzymes (ArMs) that catalyze a dozen different reactions. Despite its versatility, the homotetrameric nature of streptavidin (Sav) and the noncooperative binding of biotinylated cofactors impose two limitations on the genetic optimization of ArMs: (i) point mutations are reflected in all four subunits of Sav, and (ii) the noncooperative binding of biotinylated cofactors to Sav may lead to an erosion in the catalytic performance, depending on the cofactor:biotin-binding site ratio. To address these challenges, we report on our efforts to engineer a (monovalent) single-chain dimeric streptavidin (scdSav) as scaffold for Sav-based ArMs. The versatility of scdSav as host protein is highlighted for the asymmetric transfer hydrogenation of prochiral imines using [Cp*Ir(biot--L)Cl] as cofactor. By capitalizing on a more precise genetic fine-tuning of the biotin-binding vestibule, unrivaled levels of activity and selectivity were achieved for the reduction of challenging prochiral imines. Comparison of the saturation kinetic data and X-ray structures of [Cp*Ir(biot--L)Cl]·scdSav with a structurally related [Cp*Ir(biot--L)Cl]·monovalent scdSav highlights the advantages of the presence of a single biotinylated cofactor precisely localized within the biotin-binding vestibule of the monovalent scdSav. The practicality of scdSav-based ArMs was illustrated for the reduction of the salsolidine precursor (500 mM) to afford ()-salsolidine in 90% ee and >17 000 TONs. Monovalent scdSav thus provides a versatile scaffold to evolve more efficient ArMs for in vivo catalysis and large-scale applications.

PubMed: 31509711
DOI: 10.1021/jacs.9b06923

実験手法

X-RAY DIFFRACTION (1.85 Å)