5n8q
From Proteopedia
Structure of truncated Norcoclaurine Synthase from Thalictrum flavum
Structural highlights
FunctionNCS_THLFG Involved in the biosynthesis of the common precursor of all benzylisoquinoline alkaloids such as morphine, sanguinarine, codeine or berberine. Condenses dopamine and 4-hydroxyphenylacetaldehyde.[1] [2] [3] Publication Abstract from PubMedNorcoclaurine synthase (NCS) is a Pictet-Spenglerase that catalyzes the first key step in plant benzylisoquinoline alkaloid metabolism, a compound family that includes bioactive natural products such as morphine. The enzyme has also shown great potential as a biocatalyst for the formation of chiral isoquinolines. Here we present new high-resolution X-ray crystallography data describing Thalictrum flavum NCS bound to a mechanism-inspired ligand. The structure supports two key features of the NCS "dopamine-first" mechanism: the binding of dopamine catechol to Lys-122 and the position of the carbonyl substrate binding site at the active site entrance. The catalytically vital residue Glu-110 occupies a previously unobserved ligand-bound conformation that may be catalytically significant. The potential roles of inhibitory binding and alternative amino acid conformations in the mechanism have also been revealed. This work significantly advances our understanding of the NCS mechanism and will aid future efforts to engineer the substrate scope and catalytic properties of this useful biocatalyst. Structural Evidence for the Dopamine-First Mechanism of Norcoclaurine Synthase.,Lichman BR, Sula A, Pesnot T, Hailes HC, Ward JM, Keep NH Biochemistry. 2017 Sep 20. doi: 10.1021/acs.biochem.7b00769. PMID:28915025[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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