Structure of a flavonoid glucosyltransferase reveals the basis for plant natural product modification

TY - JOUR

T1 - Structure of a flavonoid glucosyltransferase reveals the basis for plant natural product modification

AU - Offen, W

AU - Martinez-Fleites, C

AU - Yang, M

AU - Kiat-Lim, E

AU - Davis, B G

AU - Tarling, C A

AU - Ford, C M

AU - Bowles, D J

AU - Davies, G J

PY - 2006/3/22

Y1 - 2006/3/22

N2 - Glycosylation is a key mechanism for orchestrating the bioactivity, metabolism and location of small molecules in living cells. In plants, a large multigene family of glycosyl-transferases is involved in these processes, conjugating hormones, secondary metabolites, biotic and abiotic environmental toxins, to impact directly on cellular homeostasis. The red grape enzyme UDP-glucose: flavonoid 3-O-glycosyltransferase (VvGT1) is responsible for the formation of anthocyanins, the health-promoting compounds which, in planta, function as colourants determining flower and fruit colour and are precursors for the formation of pigmented polymers in red wine. We show that VvGT1 is active, in vitro, on a range of flavonoids. VvGT1 is somewhat promiscuous with respect to donor sugar specificity as dissected through full kinetics on a panel of nine sugar donors. The three-dimensional structure of VvGT1 has also been determined, both in its 'Michaelis' complex with a UDP-glucose-derived donor and the acceptor kaempferol and in complex with UDP and quercetin. These structures, in tandem with kinetic dissection of activity, provide the foundation for understanding the mechanism of these enzymes in small molecule homeostasis.

AB - Glycosylation is a key mechanism for orchestrating the bioactivity, metabolism and location of small molecules in living cells. In plants, a large multigene family of glycosyl-transferases is involved in these processes, conjugating hormones, secondary metabolites, biotic and abiotic environmental toxins, to impact directly on cellular homeostasis. The red grape enzyme UDP-glucose: flavonoid 3-O-glycosyltransferase (VvGT1) is responsible for the formation of anthocyanins, the health-promoting compounds which, in planta, function as colourants determining flower and fruit colour and are precursors for the formation of pigmented polymers in red wine. We show that VvGT1 is active, in vitro, on a range of flavonoids. VvGT1 is somewhat promiscuous with respect to donor sugar specificity as dissected through full kinetics on a panel of nine sugar donors. The three-dimensional structure of VvGT1 has also been determined, both in its 'Michaelis' complex with a UDP-glucose-derived donor and the acceptor kaempferol and in complex with UDP and quercetin. These structures, in tandem with kinetic dissection of activity, provide the foundation for understanding the mechanism of these enzymes in small molecule homeostasis.

KW - catalysis

KW - flavonoid

KW - glycosylation

KW - structure

KW - wine

KW - SINGLE-POINT MUTATION

KW - CRYSTAL-STRUCTURE

KW - BIOSYNTHETIC-PATHWAY

KW - UDP-GLUCOSE

KW - GLYCOSYLTRANSFERASES

KW - ARABIDOPSIS

KW - COMPLEXES

KW - FAMILY

KW - BIOCATALYSTS

KW - SPECIFICITY

U2 - 10.1038/sj.emboj.7600970

DO - 10.1038/sj.emboj.7600970

M3 - Article

VL - 25

SP - 1396

EP - 1405

JO - EMBO Journal

JF - EMBO Journal

SN - 0261-4189

IS - 6

ER -