Glycoform Analysis of N-Glycans Linked to Glycoproteins Expressed in Rice Culture Cells : Predominant Occurrence of Complex Type N-Glycans
Although it has been found that plant endo-β-<I>N</I>-acetylglucosaminidase shows strong activity towards denatured glycoproteins and glycopeptides with high-mannose type <I>N</I>-glycans and free high-mannose type <I>N</I>-glycans bearing the chitobiosyl unit, the endogenous substrates for plant endoglycosidase have not yet been identified. Recently we purified and characterized an endo-β-<I>N</I>-acetylglucosaminidase from rice culture cells and identified the gene encoded (Maeda, M., and Kimura, Y., <I>Trends Glycosci. Glycotech.</I>, <B>17</B>, 205–214 (2005)). Furthermore, we found structural features of free <I>N</I>-glycans in the cells, indicating that high-mannose type species (Man<SUB>9-5</SUB>GlcNAc<SUB>1</SUB>) occur at concentration of several micromolar (μ<small>M</small>). Hence, in this study we analyzed glycoform of <I>N</I>-glycans linked to glycoproteins expressed in rice culture cells to see whether endogenous glycoproteinous substrate occurs in reasonable amounts. Structural analysis revealed that more than 95% of total <I>N</I>-glycans linked to glycoproteins in the rice cells had the plant complex type structure, including Lewis a epitope-harboring type, although high-mannose type structures account for less than 5% of total <I>N</I>-glycans.
- Bioscience, biotechnology, and biochemistry
Bioscience, biotechnology, and biochemistry 70(6), 1356-1363, 2006-06-23
Japan Society for Bioscience, Biotechnology, and Agrochemistry