4OKA

Structural-, Kinetic- and Docking Studies of Artificial Imine Reductases Based on the Biotin-Streptavidin Technology: An Induced Lock-and-Key Hypothesis

4OKA の概要

• エントリーDOI: 10.2210/pdb4oka/pdb
• 分子名称: Streptavidin, [N-(4-{[2-(amino-kappaN)ethyl]sulfamoyl-kappaN}phenyl)-5-(2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanamidato]iridium(III), IRIDIUM ION, ... (4 entities in total)
• 機能のキーワード: beta barrel, transfer hydrogenation, iridium piano stool, biotin-binding protein
• 由来する生物種: Streptomyces avidinii
• 細胞内の位置: Secreted: P22629
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 17437.11

構造登録者

Schirmer, T.,Heinisch, T. (登録日: 2014-01-22, 公開日: 2014-11-05, 最終更新日: 2023-11-08)

主引用文献

Robles, V.M.,Durrenberger, M.,Heinisch, T.,Lledos, A.,Schirmer, T.,Ward, T.R.,Marechal, J.D.
Structural, Kinetic, and Docking Studies of Artificial Imine Reductases Based on Biotin-Streptavidin Technology: An Induced Lock-and-Key Hypothesis
J.Am.Chem.Soc., 136:15676-15683, 2014

PubMed Abstract: An artificial imine reductase results upon incorporation of a biotinylated Cp*Ir moiety (Cp* = C5Me5(-)) within homotetrameric streptavidin (Sav) (referred to as Cp*Ir(Biot-p-L)Cl] ⊂ Sav). Mutation of S112 reveals a marked effect of the Ir/streptavidin ratio on both the saturation kinetics as well as the enantioselectivity for the production of salsolidine. For [Cp*Ir(Biot-p-L)Cl] ⊂ S112A Sav, both the reaction rate and the selectivity (up to 96% ee (R)-salsolidine, kcat 14-4 min(-1) vs [Ir], KM 65-370 mM) decrease upon fully saturating all biotin binding sites (the ee varying between 96% ee and 45% ee R). In contrast, for [Cp*Ir(Biot-p-L)Cl] ⊂ S112K Sav, both the rate and the selectivity remain nearly constant upon varying the Ir/streptavidin ratio [up to 78% ee (S)-salsolidine, kcat 2.6 min(-1), KM 95 mM]. X-ray analysis complemented with docking studies highlight a marked preference of the S112A and S112K Sav mutants for the SIr and RIr enantiomeric forms of the cofactor, respectively. Combining both docking and saturation kinetic studies led to the formulation of an enantioselection mechanism relying on an "induced lock-and-key" hypothesis: the host protein dictates the configuration of the biotinylated Ir-cofactor which, in turn, by and large determines the enantioselectivity of the imine reductase.

PubMed: 25317660
DOI: 10.1021/ja508258t

実験手法

X-RAY DIFFRACTION (2.505 Å)