A Novel (R)‐Imine Reductase from Paenibacillus lactis for Asymmetric Reduction of 3 H‐Indoles

Abstract

A novel (R)‐imine reductase (PlRIR) from Paenibacillus lactis was heterologously overexpressed in Escherichia coli, purified and characterized. The purified PlRIR exhibited relatively high catalytic efficiency (kcat/Km=1.58 s−1 mm−1) towards 2,3,3‐trimethylindolenine. A panel of 3H‐indoles and 3H‐indole iodides were reduced by PlRIR to yield the corresponding products with good‐to‐excellent enantioselectivity (66–98 % ee). In addition, PlRIR also possesses good activities toward other types of imines such as pyrroline, tetrahydropyridine, and dihydroisoquinoline, indicating a reasonably broad substrate acceptance. In a 100 mg scale preparative reaction, 100 mm 2,3,3‐trimethylindolenine was converted efficiently to afford (R)‐2,3,3‐trimethylindoline with 96 % ee and 81 % yield.

Extended Catalytic Scope of a Well‐Known Enzyme: Asymmetric Reduction of Iminium Substrates by Glucose Dehydrogenase

“…Although IREDs have been extensively characterized for the reduction of cyclic imines, there are few reports on the reduction of iminium salts . We aimed to characterize R ‐ and S ‐selective IREDs for the reduction of cyclic iminium salts.…”

Discovery and Engineering of a Novel Baeyer‐Villiger Monooxygenase with High Normal Regioselectivity

“…BVMO with higher activity and regioselectivity will significantly reduce the formation of by‐products, and simplify downstream separation and purification steps. The protein sequence of Pp BVMO has been employed as a probe to perform pBLAST in the NCBI database [34,35] . Pp BVMO has shown the highest catalytic activity among the four BVMOs reported, with normal selectivity toward 10‐ketostearic acid, and has been widely used in the biotransformation of unsaturated fatty acids.…”

“…The protein sequence of PpBVMO has been employed as a probe to perform pBLAST in the NCBI database. [34,35] PpBVMO has shown the highest catalytic activity among the four BVMOs reported, with normal selectivity toward 10-ketostearic acid, and has been widely used in the biotransformation of unsaturated fatty acids. To increase the diversity of candidate gene sources, we selected 13 putative genes encoding various BVMOs from bacteria having 20-80 % sequence identities with the PpBVMO template.…”

Biochemical and Structural Characterization of an (R)‐Selective Transaminase in the Asymmetric Synthesis of Chiral Hydroxy Amines

“…Various enzymatic routes, including lipasecatalyzed kinetic resolution, asymmetric reduction by imine reductase/amine dehydrogenase, oxidation by monoamine oxidase, and transaminase-mediated asymmetric amination, have been developed for chiral amines synthesis. [13][14][15][16][17][18][19] However, native reductase/ amine dehydrogenases require improvements because of their poor catalytic efficiency. [20,21] Transaminase (TA, EC 2.6.1.18) is able to reversibly catalyze the formation of amine groups with high activity and excellent stereoselectivity, by transferring an amino donor to a prochiral ketone or aldehyde.…”