New study finds novel functions of the pyruvate-sensing protein PdhR in E. Coli

September 28, 2020

Organisms, ranging from bacteria to humans, run on an interconnected series of metabolic pathways--with glycolysis being the essential process that generates energy from sugars (glucose) in food. Pyruvate is the final product of glycolysis: it is an important molecule that acts as a node between different pathways (Figure 1). To better understand how these pathways work, a team of scientists, led by Dr Tomohiro Shimada from Meiji University and including Dr Akira Ishihama from Hosei University and Dr Sousuke Imamura from Tokyo Institute of Technology (Tokyo Tech), decided to investigate a protein called "PdhR," the master regulator of pyruvate catabolism (or breakdown) in Escherichia coli (a common model organism). They knew from previous research that PdhR regulates the expression of at least nine proteins involved in carbon metabolism pathways (breakdown of sugars into energy sources). But, given the many roles of pyruvate from scavenging free radicals to generating amino acids, it was logical to think PdhR had multiple targets.

Researchers used a process called gSELEX (Genomic SELEX) screening, in which PdhR is mixed with small pieces of E. coli genome. PdhR was tagged with a marker that allowed researchers to isolate the targets of PdhR. This led to the successful identification of multiple targets of PdhR. "We were able to find 16-27 possible targets of PdhR this way," Dr Shimada explained. "And from these, we decided to analyze the ones that had never been identified before. The goal was to find new pathways involving PdhR."

The team identified PdhR regulatory targets that were involved in bacterial movement, specifically acting as a repressor of genes affecting flagella (the appendage that many bacteria use to move). They also found that PdhR regulated breakdown of fatty acids (an important energy source in bacteria) by suppressing a protein that inhibits this process. In other words, active PdhR decreases bacterial mobility and increases fatty acid degradation--functions of PdhR that are completely novel. Moreover, the scientists also identified other carbon-metabolism genes regulated by PdhR, including enzymes that produces pyruvate during glycolysis, lactate metabolism, and TCA cycle.

The scientists are optimistic that these findings from E. coli can be applied to more complex, multicellular animals. They could also help us to better manipulate E. coli metabolism, which has important implications for bioengineering and molecular biology experiments." Dr Shimada concludes, "Our work allowed us to expand the role of PdhR beyond what was already known. Because pyruvate concentrations influence PdhR activity, these results really helps us better understand the critical central role of pyruvate in E. coli metabolism. E. coli is an extremely common bacteria, and understanding it can lead to significant insights into the medical field."

Tokyo Institute of Technology

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to