0000000000326508

AUTHOR

Liqun Xia

showing 3 related works from this author

High speed X-ray analysis of plant enzymes at room temperature.

2013

X-ray measurements at room temperature (295 K) deliver high quality data sets with unprecedented speed (2 min), as shown for crystallized raucaffricine-O-β-D-glucosidase (RG), its mutant RG-Glu186Gln and several ligand complexes of the enzyme which participates in alkaloid biosynthesis in the plant Rauvolfia. The data obtained are compared with data sets measured under typical cryo conditions (100K). Under both conditions, density maps are highly comparable and favor the described protocol for room temperature measurements, potentially paving the way for future crystallographic studies capturing biosynthetic pathway intermediates.

chemistry.chemical_classificationModels MolecularRauvolfiabiologyLigandX-RaysMutantMolecular ConformationTemperaturePlant ScienceGeneral MedicineHorticulturebiology.organism_classificationBiochemistryTemperature measurementRauwolfiaCrystallographyEnzymeAlkaloidschemistryRauvolfia serpentinaHydrolaseX-ray crystallographyMolecular BiologyGlucosidasesPhytochemistry
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Structures of Alkaloid Biosynthetic Glucosidases Decode Substrate Specificity

2011

Two similar enzymes with different biosynthetic function in one species have evolved to catalyze two distinct reactions. X-ray structures of both enzymes help reveal their most important differences. The Rauvolfia alkaloid biosynthetic network harbors two O-glucosidases: raucaffricine glucosidase (RG), which hydrolyses raucaffricine to an intermediate downstream in the ajmaline pathway, and strictosidine glucosidase (SG), which operates upstream. RG converts strictosidine, the substrate of SG, but SG does not accept raucaffricine. Now elucidation of crystal structures of RG, inactive RG-E186Q mutant, and its complexes with ligands dihydro-raucaffricine and secologanin reveals that it is the…

Models MolecularRauvolfiaStereochemistryIridoid GlucosidesMolecular Sequence DataMutantCrystallography X-RayBiochemistryRauwolfiaSubstrate SpecificityEvolution Molecularchemistry.chemical_compoundHydrolaseSerineAmino Acid SequenceVinca AlkaloidsPlant Proteinschemistry.chemical_classificationBinding SitesbiologyTryptophanSubstrate (chemistry)General Medicinebiology.organism_classificationKineticsEnzymechemistryBiochemistryStrictosidinebiology.proteinMolecular MedicineSecologaninGlucosidasesGlucosidasesProtein BindingACS Chemical Biology
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Ligand structures of synthetic deoxa-pyranosylamines with raucaffricine and strictosidine glucosidases provide structural insights into their binding…

2014

Insight into the structure and inhibition mechanism of O-β-d-glucosidases by deoxa-pyranosylamine type inhibitors is provided by X-ray analysis of complexes between raucaffricine and strictosidine glucosidases and N-(cyclohexylmethyl)-, N-(cyclohexyl)- and N-(bromobenzyl)-β-d-gluco-1,5-deoxa-pyranosylamine. All inhibitors anchored exclusively in the catalytic active site by competition with appropriate enzyme substrates. Thus facilitated prospective elucidation of the binding networks with residues located at <3.9 A distance will enable the development of potent inhibitors suitable for the production of valuable alkaloid glucosides, raucaffricine and strictosidine, by means of synthesis in …

Models MolecularStereochemistryCyclopentanesLigandsRauwolfiaStructure-Activity RelationshipSugar AlcoholsRauvolfia serpentinaDrug DiscoveryHydrolasePharmacologychemistry.chemical_classificationBinding SitesDose-Response Relationship DrugMolecular StructurebiologyAlkaloidActive siteGeneral Medicinebiology.organism_classificationLigand (biochemistry)EnzymeBiochemistrychemistryStrictosidinebiology.proteinGlucosidasesGlucosidasesJournal of Enzyme Inhibition and Medicinal Chemistry
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