title: Redesign of a central enzyme in alkaloid biosynthesis.
abstract: Plant alkaloids exhibit a diverse array of structures and pharmaceutical activities, though metabolic engineering efforts in these eukaryotic pathways have been limited. Strictosidine synthase (STR) is the first committed step in the biosynthesis of over two thousand terpene indole alkaloids. We describe a rational redesign of the STR binding pocket to selectively accommodate secologanin substrate analogs. The mutant is selective for a substrate that can be chemoselectively derivatized. Evidence that this substrate can be processed by later steps of the terpene indole alkaloid pathway is provided. The work demonstrates that the central enzyme of this alkaloid pathway can be redesigned and that the pathway can turn over the unnatural intermediate that is generated. Modulation of the substrate specificity of enzymes of this complex pathway is therefore likely to enable metabolic engineering efforts of these alkaloids.
authors.affiliation: Massachusetts Institute of Technology, Department of Chemistry, 18-592, Cambridge, Massachusetts 02139, USA.
authors.forename: Shi
authors.initials: S
authors.lastname: Chen
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Galan
authors.forename: Carla
authors.initials: C
authors.lastname: Coltharp
authors.forename: Sarah E
authors.initials: SE
authors.lastname: O'Connor
mesh_terms: D019759:Carbon-Nitrogen Lyases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D026121:Indole Alkaloids / Q000378:metabolism*; D057888:Iridoid Glucosides; D039823:Iridoids / Q000378:metabolism*; D009154:Mutation; D013379:Substrate Specificity
chemical_list: D026121:Indole Alkaloids; D057888:Iridoid Glucosides; D039823:Iridoids; C021086:secologanin; D019759:Carbon-Nitrogen Lyases; C022684:strictosidine synthetase