Delgado I J, Wang Z, de Rocher A, Keegstra K, Raikhel N V
Department of Energy Plant Research Laboratory, Michigan State University, East Lansing 48824-1312, USA.
Plant Physiol. 1998 Apr;116(4):1339-50. doi: 10.1104/pp.116.4.1339.
A reversibly glycosylated polypeptide from pea (Pisum sativum) is thought to have a role in the biosynthesis of hemicellulosic polysaccharides. We have investigated this hypothesis by isolating a cDNA clone encoding a homolog of Arabidopsis thaliana, Reversibly Glycosylated Polypeptide-1 (AtRGP1), and preparing antibodies against the protein encoded by this gene. Polyclonal antibodies detect homologs in both dicot and monocot species. The patterns of expression and intracellular localization of the protein were examined. AtRGP1 protein and RNA concentration are highest in roots and suspension-cultured cells. Localization of the protein shows it to be mostly soluble but also peripherally associated with membranes. We confirmed that AtRGP1 produced in Escherichia coli could be reversibly glycosylated using UDP-glucose and UDP-galactose as substrates. Possible sites for UDP-sugar binding and glycosylation are discussed. Our results are consistent with a role for this reversibly glycosylated polypeptide in cell wall biosynthesis, although its precise role is still unknown.
豌豆（Pisum sativum）中的一种可逆糖基化多肽被认为在半纤维素多糖的生物合成中发挥作用。我们通过分离编码拟南芥（Arabidopsis thaliana）可逆糖基化多肽-1（AtRGP1）同源物的cDNA克隆，并制备针对该基因编码蛋白的抗体，对这一假设进行了研究。多克隆抗体可检测双子叶植物和单子叶植物中的同源物。我们检测了该蛋白的表达模式和细胞内定位。AtRGP1蛋白和RNA浓度在根和悬浮培养细胞中最高。该蛋白的定位表明它大多是可溶的，但也与膜周边相关。我们证实，以UDP-葡萄糖和UDP-半乳糖为底物时，在大肠杆菌中产生的AtRGP1可以被可逆糖基化。文中讨论了UDP-糖结合和糖基化的可能位点。我们的结果与这种可逆糖基化多肽在细胞壁生物合成中的作用一致，尽管其确切作用仍不清楚。
