| Abstract Detail
Metabolism Pieris, Shayani [1], Li, Li [2], Jane, Jay-lin [3], Spalding, Martin [4]. Effect of Maize SBE I on thhe nature of the alpha polyglucan produced in Synechocystis sp. PCC 6803. Glycogen and starch, the alpha(1,4) and alpha (1,6) linked glucose polymers are chemically similar but differ in glycogen being water soluble and starch, due to the presence of Amylopectin, being water insoluble/semi-crystalline. One of the factors thought to contribute towards the unique fine structure of Amylopectin which determines its’ semi-crystalline nature is the type of branching enzyme present. We tested the hypothesis that the presence of a branching enzyme that is able to transfer long chains may facilitate the formation and perpetuation of a cluster branching pattern by introducing Maize SBE I (MSBE I) into Synechocystis sp. PCC 6803 with a background of only residual glycogen branching enzyme activity, and characterized the glucan produced. The glucan was extracted using Dimethyl sulfoxide (DMSO) for characterization of size and branch chain length distribution or, was extracted, without change to its’ structure, using percoll gradient centrifugation for characterization of its’ physical nature. Our results show that the introduced maize SBE I was expressed and active and resulted in a glucose polymer with longer chains, with a peak DP of 15 and an average DP of 23, and a bimodal chain length distribution with peaks at DP 15 and DP 49. This glulcose polymer is also shown to be larger in size than glycogen produced by Wild Type Synechocystis cells. The glucan produced in vivo and the glucan extracted using percoll gradient centrifugation was Theiry stained and viewed under the Transmission electron microscope and showed similarity to each other in size and shape. These combined results indicate that MSBE I expression led to the formation of a unique glucan and suggest that transfer of long chains does impact the nature of the glucan produced.
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1 - Iowa State University, Genetics, Development and Cell Biology, Osborne Drive, Ames, IA, 50011, USA
2 - Iowa State University, Food Science and Human Nutrition
3 - Iowa State University, Food Science and Human Nutritiion
4 - Iowa State Unicersity, Genetics, Development and Cell Biology
Keywords:
Maize SBE I
Semi-crystalline Amylopectin
starch
glycogen
Synechocystis
.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P19012
Abstract ID:345 |
