title: Structure, Activity and Stereoselectivity of NADPH-Dependent Oxidoreductases Catalysing the S-Selective Reduction of the Imine Substrate 2-Methylpyrroline.
abstract: Oxidoreductases from Streptomyces sp. GF3546 [3546-IRED], Bacillus cereus BAG3X2 (BcIRED) and Nocardiopsis halophila (NhIRED) each reduce prochiral 2-methylpyrroline (2MPN) to (S)-2-methylpyrrolidine with >95 % ee and also a number of other imine substrates with good selectivity. Structures of BcIRED and NhIRED have helped to identify conserved active site residues within this subgroup of imine reductases that have S selectivity towards 2MPN, including a tyrosine residue that has a possible role in catalysis and superimposes with an aspartate in related enzymes that display R selectivity towards the same substrate. Mutation of this tyrosine residue-Tyr169-in 3546-IRED to Phe resulted in a mutant of negligible activity. The data together provide structural evidence for the location and significance of the Tyr residue in this group of imine reductases, and permit a comparison of the active sites of enzymes that reduce 2MPN with either R or S selectivity.
authors: Department of Chemistry, University of York, Heslington, York, YO10 5DD (UK).
authors: Henry
authors: H
authors: Man
authors: Elizabeth
authors: E
authors: Wells
authors: Shahed
authors: S
authors: Hussain
authors: Friedemann
authors: F
authors: Leipold
authors: Sam
authors: S
authors: Hart
authors: Johan P
authors: JP
authors: Turkenburg
authors: Nicholas J
authors: NJ
authors: Turner
authors: Gideon
authors: G
authors: Grogan
mesh_terms: D055162:Biocatalysis; D020134:Catalytic Domain; D006094:Gram-Positive Bacteria / Q000201:enzymology; D007097:Imines / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D010084:Oxidation-Reduction; D011759:Pyrrolidines / Q000737:chemistry* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: C520125:2-methylpyrrolidine; D007097:Imines; D011759:Pyrrolidines; D009247:NADH, NADPH Oxidoreductases
keywords: IREDs; NADPH; amines; asymmetric catalysis; imines; oxidoreductases