STRUCTURE BASED KINETICS IN POLYSACCHARIDES BY TIME RESOLVED X-RAY CRYSTALLOG

University Of Chicago, Chicago IL

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Abstract

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Polysaccharides comprise a distinct class of biopolymers produced universally among the living organisms. They have extensive group of different chemical structures and exhibit a variety of unique molecular and packing structures. The wide range of sources combined with the intrinsic functional behavior bestows their widespread utilization in food formulations. Further their unique properties such as renewability biodegradability and biological activity spawn the development of novel applications in pharmaceutical and medicinal uses. Many of the polysaccharides are water soluble and form the bulk of foods consumed by humans. In food formulations they are used to control the functional properties such as water binding viscosity thickening and stability of dispersions. Interestingly addition of food ingredients significantly alters their physical properties namely the solubility hydroscopicity and crystallinity. For example incorporation of sugar modifies the solvent properties whereas salt promotes gelation among the hydrocolloids. In this regard a detailed knowledge about the physical and chemical interactions among the polysaccharides and food ingredients such as salt sugar and water as well as the structural transitions that takes place during such interactions enlightens the underlying molecular mechanisms that are responsible for the macroscopic behavior of the food systems. Time resolved crystallographic studies on several protein structures have revealed a wealth of information about their chemical kinetics. We would like to utilize similar approach to unravel the kinetic mechanism in the polysaccharide matrices through a series of time-dependent crystallographic data analysis. The current proposal is about determining the architectural changes in a number of biologically important and industrially useful polysaccharides during their interactions with solvent solute and small molecules. The study includes three algal polysaccharides namely iota-carrageenan kappa-carrageenan and lambda carrageenan. We strongly believe that the outcome of this study will shed light towards deciphering the molecular mechanisms of polysaccharides leading to the development of novel functional foods with desired functionality.