Deacetylated pustulan, a (1-6)-�-D-glucan harvested from the lichen Umbilicaria papullosa, forms thermoreversible gels in water at room temperature through the development of microcrystalline junction zones following a conformational ordering and self-association process. Gelation does not occur for acetylated pustulan, or pustulan dissolved in DMSO or 4M aqueous urea solution. Viscometry, proton NMR and Nuclear Overhauser NMR (NOESY) results provide evidence for a fast (<1 hour) initial ordering of the chains from the random coil into a molecular conformation that provides the basis for the crystalline nucleation (8-9 hours) necessary for gel formation. CP/MAS 13C NMR has shown that the gel contains crystallites of the �hydrate� polymorphic form. Recent interest in (1-6)-�-D-glucan has arisen from the discovery that certain yeasts, including Saccharomyces cerevisiae, contain this polysaccharide (deacetylated) in their cell walls where it serves as a receptor for yeast proteins called �killer toxins�.  Possible mechanisms for this binding will be discussed.

NMR studies on the conformational ordering and self-association of the water-soluble polysaccharide pustulan ((1-6)-β-D-glucan)

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.