Abstract
When sporamin is expressesd in tobacco BY-2 cells, it is glycosylated at the 36th Pro with an arabinogalactan-type glycan. Taking advantage that this site is the only proline hydroxylation and glycosylation site for arabinogalactan-type glycan in sporamin, we are analyzing sequence requirement for this type glycosylation using sporamin. We have reported previously that five amino acids each before and after the glycosylation site, respectively, is indispensable for this modification. We analyzed the nature of each amiono acids in this region that are required for the glycosylation. Secretory sporamin with different amino acid substitutions were expressed in BY-2 cells and the extent of glycosylation was estimated. Mutant sporamins that were less glycosylated than wild-type were purified and analyzed by Edman degradation. Based on results of this analysis, we will discuss the sequence motifs for the Pro hydroxylation and for the glycosylation of Hyp.
