Chemistry Reference
In-Depth Information
(a)
(b)
(c)
Figure 21.2
Carbohydrate - mediated species -
specifi c intercellular adhesion in sponges. (a)
AFM images of linear and circular sponge adhe-
sion proteoglycans with 20-25 radiating arms.
(b) AFM images of native
Microciona prolifera
proteoglycan (reprinted from [1] ) . The grey -
coded vertical
z
-scale is 3 nm. The top image
shows the localization of g200 glycan in the ring
(circles) and g6 glycan in the arms (lines). The
enlarged middle image shows 15-16 domains
(dots) in each arm in the native structure. The
enlarged bottom image shows a detail of the
ring structure with short chains protruding,
which might represent the g200 glycan (lines).
(c) Schematic drawing of the current model
depicting the interaction between two sponge
cell adhesion proteoglycans (adapted from [7]).
plasmon resonance (SPR) measurements (a technique described later in this
chapter) showed that self-recognition of the carbohydrate epitopes in g200 is the
major force behind the recognition event [6] and that g200 self-adhesion is much
stronger than its binding to other unrelated glycans, such as chondroitin sulfate
( CS ) [7] .
21.2.1.2
Glycosaminoglycan Self - Interactions
It has been well established that GAGs located at the cell surface, particularly CS
and hyaluronic acid (HA), are involved in cell adhesion, organogenesis and dif-
ferentiation. However, little is known about the possible role of direct GAG-GAG
interactions in these processes. A research line related to the interaction between
GAGs demonstrated the specifi c
in vitro
binding between carbohydrate chains of
CS and HA coated onto beads [8]. The authors suggested that specifi c binding
between heterologous GAG chains can represent one mechanism controlling
adhesive behavior and morphogenetic phenomena.
