9r76

Publication Abstract from PubMed

Imine reductases with an (S)-preference for the reduction of the model substrate 2-methyl pyrroline typically contain tyrosine in the active site (Y-IREDs) instead of the aspartate present within (R)-selective enzymes (D-IREDs). As with D-IREDs, a subset of Y-IREDs is capable of enabling reductive amination reactions between some ketone and amine partners to give optically active amines with high optical purity. However, structures of Y-IREDs in complex with the substrates and products of the reductive amination have not been forthcoming. Herein, structures of the Y-IRED IR91 from Kribbella flavida in complex with 5-methoxy-2-tetralone, a synthetic precursor to the anti-Parkinson's treatment rotigotine, and also its reductive amination product with methylamine, 5-methoxy-(S)-2-(N-methylamino)-tetralin, are presented. The structures, in combination with mutation and kinetic studies, support a role for tryptophan residue W258 in the activity of the enzyme, possibly in binding of the ketone prior to reaction with methylamine.

Structures of "Tyrosine-IRED" IR91 from Kribbella flavida in Complex with a Reductive Amination Substrate and Product.,Srinivas K, Gilio AK, Sharma M, Green L, Ascham A, Domenech J, Pogranyi B, Li J, France SP, Lewis RD, Unsworth WP, Grogan G Chembiochem. 2025 Sep 15;26(17):e202500450. doi: 10.1002/cbic.202500450. Epub , 2025 Jul 29. PMID:40727968^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.