Actinomycetes-derived imine reductases with a preference towards bulky amine substrates

Abstract

Since imine reductases (IREDs) were reported to catalyze the reductive amination reactions, they became particularly attractive for producing chiral amines. Though diverse ketones and aldehydes have been proved to be excellent substrates of IREDs, bulky amines have been rarely transformed. Here we report the usage of an Increasing-Molecule-Volume-Screening to identify a group of IREDs (IR-G02, 21, and 35) competent for accepting bulky amine substrates. IR-G02 shows an excellent substrate scope, which is applied to synthesize over 135 amine molecules as well as a range of APIs’ substructures. The crystal structure of IR-G02 reveals the determinants for altering the substrate preference. Finally, we demonstrate a gram-scale synthesis of an analogue of the API sensipar via a kinetic resolution approach, which displays ee >99%, total turnover numbers of up to 2087, and space time yield up to 18.10 g L−1 d−1.

Biocatalytic reductive aminations with NAD(P)H-dependent enzymes: enzyme discovery, engineering and synthetic applications

“…109 Later, bulky amines as donors have been included into the scope (Table 3, entry 36). 139 Large panel screenings and further engineering efforts have enabled a number of target pharmaceuticals to be synthesized by IREDs. Zhan et al developed the IRED catalyzed synthesis of a key intermediate to the tyrosine kinase inhibitor Tofacitinib, which has been a successful drug commercialized in more than 50 countries.…”

Asymmetric Reductive Amination in Organocatalysis and Biocatalysis

“…In 2022, Cui's group screened and discovered IRED: IR-G02, an enzyme with the potential to catalyse a wide range of amines. [89] They further elucidated its structure and performed targeted mutagenesis, resulting in the highly enantioselective synthesis of 1-(1-Naphthyl)ethylamine with a selectivity of over 99 %.…”

Engineered Biocatalysts for Enantioselective Reductive Aminations of Cyclic Secondary Amines

“…Although the scope of primary amines that can be coupled is continuing to expand, including sterically hindered substrates, [15,16] secondary amines remain problematic. This challenge is particularly acute when using piperidines and related substrates as the amine and ketones as the coupling partner.…”

“…substrates, [15,16] secondary amines remain problematic. This challenge is particularly acute when using piperidines and related substrates as the amine and ketones as the coupling partner.…”