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Allosteric activation of PykF by HPr Allosteric activation of PfkB by HP Allosteric activation of NagB by HPr Inhibition of ATP-dependent Adk by Hpr-P
Protein-Protein Interactions
Coupled Assays

Journal of Comprehensible Results

Rodionova IA, Zhang Z, Mehla J, Goodacre N, Babu M, Emili A, Uetz P, Saier MH Jr. (2017)
The phosphocarrier protein HPr of the bacterial phosphotransferase system globally
regulates energy metabolism by directly interacting with multiple enzymes in Escherichia coli
J Biol Chem. 2017 Aug 25;292(34):14250-14257

(Translated by Shravani Wadwekar)

Introduction

HPr is a phosphocarrier protein that is essential to the PTS, as the protein regulates the sugar transport, which plays an important role in bacteria, such as E. coli, a bacterium commonly found in the lower intestine. HPr has been found to interact with several carbohydrate-metabolizing enzymes in the PTS, yet the level of regulation is still unclear. E. coli contains four proteins: PykF, PfkB, NagB, and Adk; Rodionova et. al (2017) measures the activity of HPr in the presence of each E. coli protein and observe the protein-protein interactions that occur.

Pykf is a pyruvate kinase, which essentially catalyzes the transfer of a phosphate group from PEP (a pyruvate, or a salt of pyruvic acid) to ADP (provides energy to catalyze processes), ending in 1 molecule of pyruvate and 1 molecule of ATP (also provides energy to catalyze processes). PfkB (phosphofructokinase) is an enzyme that regulates the breakdown and phosphorylation of sugar due to the transfer of a phosphate group from ATP.

NagB (glucosamine-6-phosphate deaminase) is an enzyme the catalyzes the breakdown of the sugar glucosamine to the sugar fructose and an NH3 group. Adk (adenylate kinase) catalyzes the interconversion of ATP, ADP, and AMP (all molecules that provide energy for chemical processes; only differ in number of phosphate groups), and plays an important role in keeping cellular energy at homeostasis by breaking down substances that may disrupt homeostasis.

So, the main question is: does HPr interact with these proteins and do we see a change in their activity?


Figure ii. Figure shows the complexes between HPr and PykF, PfkB, NagB, and Adk. The green presents HPr and the purple represents the E. coli protein.

Adapted from "The phosphocarrier protein HPr of the bacterial phosphotransferase system globally regulates energy metabolism by directly interacting with multiple enzymes in Escherichia coli." by Rodionova IA, Zhang Z, Mehla J, Goodacre N, Babu M, Emili A, Uetz P, Saier MH Jr., 2017, J Biol Chem, Page 14254.