Properties of two N-linked glycoproteins associated with the nuclear envelope in mung bean [Vigna radiata] hypocotyls
1995
Odaira, M. (Hokkaido Univ., Sapporo (Japan). Inst. of Low Temperature Science) | Arakawa, K. | Yoshida, S. | Maeshima, M.
Nuclei from mung bean (Vigna radiata) hypocotyls contained two glycoprotein of 50 and 49 kDa, respectively, that reacted with concanavalin A. The glycoproteins were released from the nuclear envelope by treatment with 2 M KCl but not with nucleases. The glycoproteins, tentatively named gp50 and gp49, were isolated and characterized. Gel-permeation chromatography suggested that gp50 and gp49 seem to exist as a complex with other components. The glycoproteins could be detected only in the nuclear fraction by immunoblot analysis with specific antibodies, and they were not detected in endoplasmic reticulum, plasma membrane, vacuolar membrane or mitochondria. Agglutinin I from Ulex europeaus, peanut agglutinin, soybean agglutinin and wheat germ agglutinin all failed to bind to the glycoproteins. Treatment with glycopeptidase F removed all oligosaccharides from the glycoproteins and decreased their molecular masses by about one thousand daltons each. These results suggest that the glycoproteins contained N-linked, high-mannose-type oligosaccharides with six or seven hexose residues. gp50 and gp49 seemed to be isoforms of a single glycoprotein because the two proteins had some common properties. Nuclear factions from adzuki bean (Phaseolus angularis) and soybean (Glycine max) contained proteins that were immunologically similar to gp50 and gp49
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