Exploring the molecular structure of starch granule during the initial stages of granule formation

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Starch remains a subject of intense scientific interest because of the structural complexity of this self-assembling macromolecule. Within in the context of starch structure and architecture, the initiation of granule formation remains unclear. While theories have been proposed from genetics and biochemistry points of view, research to-date has not really taken into account the physical and structural features of starch polymers with respect to their role in granule initiation and early granule development. Research proposed herein, aims to bridge this gap; i.e., to determine the molecular architecture of the early polymers/granules as influenced by different biosynthetic enzymes. Our short-term goal is to determine the molecular architecture of polymers at early stages of starch granule development to likely explain the mechanism of granule initiation. We propose to test this premise in both transient and storage starches. It is our hypothesis that the molecular organization at early stages of granule development is conserved in both transient and storage starches; and that this structure is likely closely linked to the events of granule initiation. The objectives of this research, therefore, are to; 1) Characterize the structural and morphological properties of transient starch granules, and the molecular structure of amylose and amylopectin of starches at different photoperiods; and 2) Characterize the structural and morphological properties of granules, and the molecular structure of amylose and amylopectin of developing maize storage starches.The scientific approach for both objectives include the use of enzymatic methods combined with chromatography for characterization of molecular components and their fine structures, X-ray scattering and calorimetry to study the molecular organization in semi-crystalline parts, microscopy to study the morphology of supramolecular structures. The proposed project is novel because the unit chain organization of developing starch polymers in transient or storage starches has never been analyzed previously. Also, results from this project will contribute to an understanding of the likely mechanisms of granule initiation; knowledge that is as yet unknown.