Sugar activation for production of nucleotide sugars as substrates for glycosyltransferases in plants
J Appl Glycoscience 2015, 62(2):25-36
Kleczkowski LA, Decker D

Abstract
The family of glycosyltransferases includes hundreds of proteins, most of which are using NDP-sugar as one of the substrates. In order to serve as a glycosyl donor, a sugar or a sugar derivative (e.g. GlcA) needs to be “activated” to a highly energetic state of a nucleotide-sugar. This activation requires the involvement of specific enzymes which attach NDP (or, in one case, NMP) to a given sugar, using NTP or NDP as substrate. The present review provides concise survey of distinct plant nucleotidesugar pyrophosphorylases (all using NTP as one of the substrates and differing in sugar specificity) as well as nucleotide-sugar phosphorylases and sucrose synthase (all using NDP as one of substrates). The pyrophosphorylases discussed include UGPase, USPase, UAGPase, AGPase, GMPase (VTC1) and FKGP, whereas phosphorylases include ADP-Glc phosphorylase and GDP-Gal phosphorylase (VTC2/VTC5). We also discuss the activation mechanism of 3-deoxy-D-manno-octulosonic acid (Kdo) by CKS, leading to the formation of a unique NMP-linked sugar (CMP-Kdo).

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