Dem IPB wird erneut ein beispielhaftes Handeln im Sinne einer chancengleichheitsorientierten Personal- und Organisationspolitik bescheinigt. Das Institut erhält zum 6. Mal in Folge das TOTAL E-QUALITY…
Die Plant Science Student Conference (PSSC) wird seit 20 Jahren im jährlichen Wechsel von Studierenden der beiden Leibniz-Institute IPK und IPB organisiert. Im Interview erläutern Christina Wäsch…
Brandt, W.; Schulze, E.; Liberman-Aloni, R.; Bartelt, R.; Pienkny, S.; Carmeli-Weissberg, M.; Frydman, A.; Eyal, Y.;Structural modeling of two plant UDP-dependent sugar-sugar glycosyltransferases reveals a conserved glutamic acid residue that is a hallmark for sugar acceptor recognitionJournal of Structural Biology213107777(2021)DOI: 10.1016/j.jsb.2021.107777
Glycosylation is one of the common modifications of plant metabolites, playing a major role in the chemical/biological diversity of a wide range of compounds. Plant metabolite glycosylation is catalyzed almost exclusively by glycosyltransferases, mainly by Uridine-diphosphate dependent Glycosyltransferases (UGTs). Several X-ray structures have been determined for primary glycosyltransferases, however, little is known regarding structure–function aspects of sugar-sugar/branch-forming O-linked UGTs (SBGTs) that catalyze the transfer of a sugar from the UDP-sugar donor to an acceptor sugar moiety of a previously glycosylated metabolite substrate.In this study we developed novel insights into the structural basis for SBGT catalytic activity by modelling the 3d-structures of two enzymes; a rhamnosyl-transferase Cs1,6RhaT – that catalyzes rhamnosylation of flavonoid-3-glucosides and flavonoid-7-glucosides and a UGT94D1 – that catalyzes glucosylation of (+)-Sesaminol 2-O-β-Dglucoside at the C6 of the primary sugar moiety.Based on these structural models and docking studies a glutamate (E290 or E268 in Cs1,6RhaT or UGT94D1, respectively) and a tryptophan (W28 or W15 in Cs1,6RhaT or UGT94D1, respectively) appear to interact with the sugar acceptor and are suggested to be important for the recognition of the sugar-moiety of the acceptorsubstrate.Functional analysis of substitution mutants for the glutamate and tryptophan residues in Cs1,6RhaT further support their role in determining sugar-sugar/branch-forming GT specificity.Phylogenetic analysis of the UGT family in plants demonstrates that the glutamic-acid residue is a hallmark of SBGTs that is entirely absent from the corresponding position in primary UGTs.