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Using Microtiter Dish Radiolabeling for Multiple In Vivo Measurements Of Escherichia coli pppGpp Followed by Thin Layer Chromatography
Published on: June 4, 2019
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Sound the (Smaller) Alarm: The Triphosphate Magic Spot Nucleotide pGpp
Areej Malik1, Megan A Hept1, Erin B Purcell1
1Old Dominion University, Department of Chemistry and Biochemistry, Norfolk, Virginia, USA.
Infection and Immunity
|March 15, 2023
Summary
The bacterial stringent response involves a newly recognized alarmone, triphosphate (pGpp), alongside established ones. This molecule plays a distinct role beyond mimicking longer alarmones, with unique protein interactions and synthesis in pathogens like Clostridioides difficile.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Physiology
Background:
- The bacterial stringent response is a crucial survival mechanism.
- This response is primarily regulated by guanosine tetra- and pentaphosphate alarmones (p)ppGpp.
- A third alarmone, triphosphate (pGpp), has recently gained attention.
Purpose of the Study:
- To investigate the role of pGpp in bacterial physiology.
- To determine if pGpp is merely a mimic of (p)ppGpp or has distinct functions.
- To explore the synthesis and binding properties of pGpp.
Main Methods:
- Analysis of alarmone synthesis pathways.
- Investigation of protein-alarmone interactions.
- Comparative studies of alarmone functions in different bacterial species.
Main Results:
- pGpp is synthesized through multiple pathways, utilizing GMP, (p)ppGpp, or GDP/GTP.
- pGpp has been confirmed as a deliberate synthetic product, not an artifact.
- pGpp exhibits unique protein binding capabilities and is the sole alarmone produced by Clostridioides difficile.
Conclusions:
- pGpp is a distinct alarmone with a biological role beyond functional overlap with (p)ppGpp.
- The synthesis and function of pGpp are independent of the cell's guanine nucleotide pool.
- pGpp plays a significant role in the physiology of certain bacteria, including pathogens.
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