h Center, Academia Sinica, Taiwan. Conflicts of Interest: The authors declare no conflict of interest.
Analysis ARTICLEStructural studies of codeinone reductase reveal novel insights into aldo-keto reductase function in benzylisoquinoline alkaloid biosynthesisReceived for publication, April 25, 2021, and in revised type, September 15, 2021 Published, Papers in Press, September 20, 2021, doi.org/10.1016/j.jbc.2021.Samuel C. Carr1, Megan A. Torres1, Jeremy S. Morris1, Peter J. Facchini1 , and Kenneth K. S. Ng1,2, From the 1Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada; 2Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, CanadaEdited by Joseph JezBenzylisoquinoline alkaloids (BIAs) are a class of specialized metabolites using a diverse selection of chemical structures and physiological effects. Codeine and CDC Inhibitor custom synthesis morphine are two closely connected BIAs with specifically beneficial analgesic properties. The aldo-keto reductase (AKR) codeinone reductase (COR) catalyzes the final and penultimate methods in the biosynthesis of codeine and morphine, respectively, in opium poppy (Papaver somniferum). On the other hand, the structural determinants that mediate substrate recognition and catalysis are certainly not effectively defined. Right here, we describe the crystal structure of apo-COR determined to a resolution of 2.4 by molecular replacement making use of chalcone reductase as a search model. Structural comparisons of COR to closely connected plant AKRs and more distantly connected homologues reveal a novel conformation within the 11 loop adjacent for the BIA-binding pocket. The proximity of this loop to several hugely conserved active-site residues along with the anticipated place of your nicotinamide ring in the NADP(H) cofactor suggest a model for BIA recognition that implies roles for a number of important residues. Utilizing site-directed mutagenesis, we show that substitutions at Met-28 and His120 of COR bring about alterations in AKR activity for the important and minor substrates codeinone and neopinone, respectively. Our findings offer a framework for understanding the molecular basis of substrate recognition in COR and also the closely associated 1,2-dehydroreticuline reductase accountable for the second half of a stereochemical inversion that initiates the morphine biosynthesis pathway.Opiates are vital and currently irreplaceable medicines for the management of serious pain associated with serious burns, postoperative recovery, cancer remedy, and palliative care (1). Globally, the licit demand for eight billion defined everyday doses per year (459 tons of morphine equivalents) is almost entirely supplied by the agricultural production of opium poppy plants in Turkey, Tasmania, and Eastern Europe (2). Though several opiate pharmaceuticals are isolated straight in the plant (e.g., morphine and codeine), other folks are derived from the structurally connected, nonmedicinal alkaloid thebaine toyield a suite of semisynthetic opiates with refined pharmacological properties (e.g., oxycodone, hydrocodone, and buprenorphine (two)). Driven by the significant capital investment required to establish pharmaceutical manufacturing capacity, coupled with the challenges of sustaining agricultural productivity in an increasingly unpredictable climate and securing worldwide supply chains within a often unstable geopolitical environment, recent BRD3 Inhibitor list consideration has focused on the potential biosynthesis of medicinal opiates in engineered microorganisms. Heterologous production systems also deliver new opportu
