CARBOHYDRATE AND GLYCOPEPTIDE INTERACTIONS WITH LECTINS

Project: Research project

Project Details

Description

Carbohydrates on the surface of both normal and transformed
cells function as receptor determinants in various biological
recognition processes. Three classes of these covalently bound
molecules are called high mannose, complex, and hybrid type
oligosaccharides, which each form a variety of structures.
Although they function as cell surface receptors, little is known
of the molecular binding properties of these oligosaccharides,
other than they are substrates for glycosylases, and that they bind
to lectins. Lectins are plant and animal proteins which bind to
specific carbohydrate determinants without modifying them.
Plant lectins have a wide number of biological applications,
including their use in exploring the structure and dynamic
properties of the membranes of normal and transformed cells.
Among the more widely employed plant metallolectins are
Concanavalin A (Con A), and the lentil (LcH), pea (PSA), soybean
(SBA) and lima-bean (LBL) lectins, all of which possess different
binding specificities, and a range of different biological activities.

Our objectives are to determine the molecular binding
mechanisms of high mannose complex, and hybrid type
glycopeptides and related synthetic oligosaccharides with lectins
in order to investigate the molecular recognition determinants of
these cell surface receptors. The spectroscopic properties of the
lectins including their bound metal ions will be investigated, since
the metal ions can serve as intrinsic reporter groups for
monitoring the interactions of the carbohydrates with the
proteins. Our discovery of a method of preparing metal ion
derivatives of LcH and PSA now makes in possible to study the
interactions of these two lectins, in addition to the other lectins,
with the carbohydrates by a variety of spectroscopic techniques,
including nuclear magnetic resonance (NMR), electron spin
resonance (EPR) and spin-echo, and circular dichroism (CD)
measurements. NMR techniques will include solvent proton NMR
dispersion measurements, and high resolution 1H, 19F, 13C, and
113Cd NMR experiments. These studies will provide direct data
on the molecular binding properties of these important classes of
cell surface carbohydrates, as well as the binding specificities of
the lectins.
StatusFinished
Effective start/end date1/1/901/1/90

Funding

  • National Cancer Institute

ASJC

  • Spectroscopy

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