A NADH-accepting imine reductase variant: Immobilization and cofactor regeneration by oxidative deamination

Sequence‐Based In‐silico Discovery, Characterisation, and Biocatalytic Application of a Set of Imine Reductases

“…Both ( R )‐ and ( S )‐selective IREDs are relatively common in bacteria (particularly in actinomycetes) and all known members of this enzyme family share the same overall structure: a dimer formed through reciprocal domain swapping between two monomers that consist of an N‐terminal, cofactor‐binding Rossmann fold motif and a helical C‐terminal domain. The preferred cofactor is generally NADPH, but it has been shown that structure‐guided protein engineering can be used to increase the specific activity of IREDs towards the non‐phosphorylated nicotinamide cofactor (NADH) . Moreover, it has been found that IREDs are not limited to reducing cyclic imines but that they are also capable of coupling carbonyl compounds and amines in a reductive amination reaction, albeit at often drastically reduced rates –.…”

Photometric Characterization of the Reductive Amination Scope of the Imine Reductases from Streptomyces tsukubaensis and Streptomyces ipomoeae

“…Interestingly, 1,10‐disubstituted (spiro)tetrahydroisoquinolines bearing a nitrogen‐substituted quaternary carbon center were also recently prepared by this route . IREDs offer a NAD(P)H‐dependent reductive approach: reduction of cyclic imine substrates (referred to as imine reduction) was described first, followed by the discovery of the capability of IREDs to reduce acyclic imines formed in situ from the respective ketones and amines (referred to as reductive amination of ketones) …”

Switching the Cofactor Specificity of an Imine Reductase

“…Recently, the group of Höhne reported the generation of an IRED variant by rational design demonstrating a three‐fold increased activity for NADH with 10 % activity recovery . To address this important challenge of improving the specificity and activity for NADH, we altered the cofactor specificity of the R ‐selective IRED from Myxococcus stipitatus ( R ‐IRED_ Ms ) by using the recently described online tool “Cofactor Specificity Reversal—Structural Analysis and Library Design” (CSR‐SALAD), developed in the lab of Frances H. Arnold.…”

“…[32,33] Recently,t he group of Hçhner eported the generation of an IRED variant by rational design demonstrating at hree-fold increaseda ctivity for NADH with 10 %a ctivity recovery. [34] To address this important challenge of improving the specificitya nd activity for NADH, we altered the cofactor specificity of the R-selectiveI RED from Myxococcus stipitatus (R-IRED_Ms)b yu sing the recently described online tool "Cofactor Specificity Reversal-Structural Analysis and LibraryD esign" (CSR-SALAD), developedi nt he lab of Frances H. Arnold.C SR-SALAD is as emirational structure-guided approacht hat aims at reversing the nicotinamide cofactors pecificity of enzymes with Rossman In the last years, imine reductases (IREDs)h ave gained importance for the formation of chiral amines by catalyzing asymmetric reductions of imines and chemo-and stereoselective reductive aminations. However,a ll characterizedm embers of this steadily growing enzyme family demonstrated strict preference for NADPH,w hiche ntails reducedp ossibilities for efficient cofactor regenerations and limitations in the construction of whole cell systems.…”