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Biochemistry

Loyola University Chicago

Starch

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Full-Text Articles in Life Sciences

Resurrecting The Regulatory Properties Of The Ostreococcus Tauri Adp-Glucose Pyrophosphorylase Large Subunit, Carlos M. Figueroa, Misty L. Kuhn, Benjamin L. Hill, Alberto A. Iglesias, Miguel A. Ballicora Oct 2018

Resurrecting The Regulatory Properties Of The Ostreococcus Tauri Adp-Glucose Pyrophosphorylase Large Subunit, Carlos M. Figueroa, Misty L. Kuhn, Benjamin L. Hill, Alberto A. Iglesias, Miguel A. Ballicora

Chemistry: Faculty Publications and Other Works

ADP-glucose pyrophosphorylase (ADP-Glc PPase) catalyzes the first committed step for the synthesis of glycogen in cyanobacteria and starch in green algae and plants. The enzyme from cyanobacteria is homotetrameric (α4), while that from green algae and plants is heterotetrameric (α2β2). These ADP-Glc PPases are allosterically regulated by 3-phosphoglycerate (3PGA, activator) and inorganic orthophosphate (Pi, inhibitor). Previous studies on the cyanobacterial and plant enzymes showed that 3PGA binds to two highly conserved Lys residues located in the C-terminal domain. We observed that both Lys residues are present in the small (α) subunit of the Ostreococcus tauri enzyme; however, one of these …


Starch Synthesis In Ostreococcus Tauri: The Starch-Binding Domains Of Starch Synthase Iii-B Are Essential For Catalytic Activity, Julieta Barchiesi, Maria Belen Velazquez, Nicolas Palopoli, Alberto A. Iglesias, Diego F. Gomez-Casati, Miguel A. Ballicora, Maria Victoria Busi Oct 2018

Starch Synthesis In Ostreococcus Tauri: The Starch-Binding Domains Of Starch Synthase Iii-B Are Essential For Catalytic Activity, Julieta Barchiesi, Maria Belen Velazquez, Nicolas Palopoli, Alberto A. Iglesias, Diego F. Gomez-Casati, Miguel A. Ballicora, Maria Victoria Busi

Chemistry: Faculty Publications and Other Works

Starch is the major energy storage carbohydrate in photosynthetic eukaryotes. Several enzymes are involved in building highly organized semi-crystalline starch granules, including starch-synthase III (SSIII), which is widely conserved in photosynthetic organisms. This enzyme catalyzes the extension of the α-1,4 glucan chain and plays a regulatory role in the synthesis of starch. Interestingly, unlike most plants, the unicellular green alga Ostreococcus tauri has three SSIII isoforms. In the present study, we describe the structure and function of OsttaSSIII-B, which has a similar modular organization to SSIII in higher plants, comprising three putative starch-binding domains (SBDs) at the N-terminal region and …