Biology Reference
In-Depth Information
Chapter 44
Rapid and High-Throughput
N
-Glycomic Analysis of Plant
Glycoproteins
Kentaro Kaneko , Takeshi Shiraya , Toshiaki Mitsui ,
and Shin-ichiro Nishimura
Abstract
Glycoprotein is a major element in higher organisms including mammalians and plants. It is widely accepted
that variation in cellular
N
-glycome is related to modulation in dynamic cellular mechanisms such as cell-cell
adhesion, cell activation, and malignant alterations in mammalian cells. However, the physiological impor-
tance of glycan modifi cation of glycoproteins in plant cells is still a matter of dispute. Therefore, a compre-
hensive and high-throughput analysis of
N
-glycome in plant glycoproteins is needed. Here, an application
of the glycoblotting-mass spectrometry technique to plant glycoprotein research is described.
Key words
AmyI-1, BlotGlyco beads, Glycoblotting, N-glycome, Plant glycoprotein
1
Introduction
Most of the proteins in higher animals and plants are glycopro-
teins bearing an N-linked oligosaccharide side chain. The consen-
sus sequence Asn-X-Ser/Thr is found in this sugar chain
binding-site of plant glycoprotein, and the reducing group of the
sugar chain binds to the nitrogen atom of the asparagine residue
[
1
,
2
]. N-linked oligosaccharide chains conjugated to plant gly-
coproteins typically have a common core structure, and are clas-
sifi ed into high mannose- and complex-type glycan chains. The
structure of the high mannose-type glycan chain is Man
(5-9)
GlcNAc
2
, while the complex-type glycan chain shows a diverse
structure, with the terminal sugars
N
-acetylglucosamine, xylose,
fucose, and galactose added to the core structure. The conjuga-
tion of
1,2-xylose residue to the core structure
is peculiar to plant glycoprotein [
2
-
4
]. Moreover, the small oli-
gosaccharide chains, called paucimannosidic-type glycans, in
which the xylose and/or fucose residue is conjugated to the core
structure of Man
(2-3)
GlcNAc
2
, are frequently observed in plant
cells [
5
]. The plant glycans containing sugar with electric charge,
α
1,3-fucose and
β
