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Full-Text Articles in Physical Sciences and Mathematics
A Critical Inter-Subunit Interaction For The Transmission Of The Allosteric Signal In The Agrobacterium Tumefaciens Adp-Glucose Pyrophosphorylase, Hiral Patel, Gabriela Martinez-Ramirez Ms., Emily Dobrzynski, Alberto A. Iglesias, Dali Liu, Miguel Ballicora
A Critical Inter-Subunit Interaction For The Transmission Of The Allosteric Signal In The Agrobacterium Tumefaciens Adp-Glucose Pyrophosphorylase, Hiral Patel, Gabriela Martinez-Ramirez Ms., Emily Dobrzynski, Alberto A. Iglesias, Dali Liu, Miguel Ballicora
Chemistry: Faculty Publications and Other Works
ADP-glucose pyrophosphorylase is a key regulatory enzyme involved in starch and glycogen synthesis in plants and bacteria, respectively. It has been hypothesized that inter-subunit communications are important for the allosteric effect in this enzyme. However, no specific interactions have been identified as part of the regulatory signal. The enzyme from Agrobacterium tumefaciens is a homotetramer allosterically regulated by fructose 6-phosphate and pyruvate. Three pairs of distinct subunit-subunit interfaces are present. Here we focus on an interface that features two symmetrical interactions between Arg11 and Asp141 from one subunit with residues Asp141 and Arg11 of the neighbor subunit, respectively. Previously, scanning …
Site-Directed Mutagenesis Of Serine-72 Reveals The Location Of The Fructose 6-Phosphate Regulatory Site Of The Agrobacterium Tumefaciensadp-Glucose Pyrophosphorylase, Mashael Alghamdi Dr., Rania Ali Z Hussien, Yuanzhang Zheng, Hiral Patel, Matias D. Asencion Diez, Alberto A. Iglesias, Dali Liu, Miguel A. Ballicora
Site-Directed Mutagenesis Of Serine-72 Reveals The Location Of The Fructose 6-Phosphate Regulatory Site Of The Agrobacterium Tumefaciensadp-Glucose Pyrophosphorylase, Mashael Alghamdi Dr., Rania Ali Z Hussien, Yuanzhang Zheng, Hiral Patel, Matias D. Asencion Diez, Alberto A. Iglesias, Dali Liu, Miguel A. Ballicora
Chemistry: Faculty Publications and Other Works
The allosteric regulation of ADP–glucose pyrophosphorylase is critical for the biosynthesis of glycogen in bacteria and starch in plants. The enzyme from Agrobacterium tumefaciens is activated by fructose 6-phosphate (Fru6P) and pyruvate (Pyr). The Pyr site has been recently found, but the site where Fru6P binds has remained unknown. We hypothesize that a sulfate ion previously found in the crystal structure reveals a part of the regulatory site mimicking the presence of the phosphoryl moiety of the activator Fru6P. Ser72 interacts with this sulfate ion and, if the hypothesis is correct, Ser72 would affect the interaction with Fru6P and activation …
Mapping Of A Regulatory Site Of The Escherichia Coli Adp-Glucose Pyrophosphorylase, Jaina A. Bhayani, Benjamin L. Hill, Anisha Sharma, Alberto A. Iglesias, Kenneth W. Olsen, Miguel A. Ballicora
Mapping Of A Regulatory Site Of The Escherichia Coli Adp-Glucose Pyrophosphorylase, Jaina A. Bhayani, Benjamin L. Hill, Anisha Sharma, Alberto A. Iglesias, Kenneth W. Olsen, Miguel A. Ballicora
Chemistry: Faculty Publications and Other Works
The enzyme ADP-glucose pyrophosphorylase (ADP-Glc PPase) controls the biosynthesis of glycogen in bacteria and starch in plants. It is regulated by various activators in different organisms according to their metabolic characteristics. In Escherichia coli, the major allosteric activator is fructose 1,6-bisphosphate (FBP). Other potent activator analogs include 1,6-hexanediol bisphosphate (HBP) and pyridoxal 5′-phosphate (PLP). Recently, a crystal structure with FBP bound was reported (PDB ID: 5L6S). However, it is possible that the FBP site found is not directly responsible for the activation of the enzyme. We hypothesized FBP activates by binding one of its phosphate groups to …
On The Roles Of Wheat Endosperm Adp-Glucose Pyrophosphorylase Subunits, Danisa M. L. Ferrero, Matias D. Asencion Diez, Misty L. Kuhn, Christine A. Falaschetti, Claudia V. Piattoni, Alberto A. Iglesias, Miguel A. Ballicora
On The Roles Of Wheat Endosperm Adp-Glucose Pyrophosphorylase Subunits, Danisa M. L. Ferrero, Matias D. Asencion Diez, Misty L. Kuhn, Christine A. Falaschetti, Claudia V. Piattoni, Alberto A. Iglesias, Miguel A. Ballicora
Chemistry: Faculty Publications and Other Works
The ADP-glucose pyrophosphorylase from wheat endosperm controls starch synthesis in seeds and has unique regulatory properties compared to others from this family. It comprises two types of subunits, but despite its importance little is known about their roles. Here, we synthesized de novo the wheat endosperm ADP-glucose pyrophosphorylase small (S) and large (L) subunit genes, heterologously expressed them in Escherichia coli, and kinetically characterized the recombinant proteins. To understand their distinct roles, we co-expressed them with well characterized subunits from the potato tuber enzyme to obtain hybrids with one S subunit from one source and an L subunit from …
Allosteric Control Of Substrate Specificity Of The Escherichia Coli Adp-Glucose Pyrophosphorylase, Ana C. Ebrecht, Ligin Solamen, Benhamin L. Hill, Alberto A. Iglesias, Ken W. Olsen, Miguel A. Ballicora
Allosteric Control Of Substrate Specificity Of The Escherichia Coli Adp-Glucose Pyrophosphorylase, Ana C. Ebrecht, Ligin Solamen, Benhamin L. Hill, Alberto A. Iglesias, Ken W. Olsen, Miguel A. Ballicora
Chemistry: Faculty Publications and Other Works
The substrate specificity of enzymes is crucial to control the fate of metabolites to different pathways. However, there is growing evidence that many enzymes can catalyze alternative reactions. This promiscuous behavior has important implications in protein evolution and the acquisition of new functions. The question is how the undesirable outcomes of in vivo promiscuity can be prevented. ADP-glucose pyrophosphorylase from Escherichia coli is an example of an enzyme that needs to select the correct substrate from a broad spectrum of alternatives. This selection will guide the flow of carbohydrate metabolism toward the synthesis of reserve polysaccharides. Here, we show that …