Spectroscopic and stoicheiometric characterisation of the calcium-mediated association of pectate chains in gels and in the solid state

Abstract

Circular dichroism and stoicheiometric evidence is presented, which indicates that the calcium-mediated association of pectate chains under hydrated conditions occurs by a pairwise mechanism in which the chains adopt two fold symmetry; this contrasts with the known three-fold conformation into which the chains convert in the solid state, and represents an unusual example of an ordered polysaccharide tertiary structure which is stabilised by high levels of hydration.