AUG 16, 2016 10:31 AM PDT

Enzymes in E.coli Will Compensate for Disabled Genes

WRITTEN BY: Carmen Leitch
Analyzing the adaptability of bacteria, biologist Shelley Copley has announced the results of research in the area at the 2nd American Society for Microbiology Conference on Experimental Microbial Evolution on August 4. It was found that when bacteria lost enzymes that are needed for certain chemical reactions, other enzymes were able to patch together a fix that fulfilled those missing functions. The video below describes the announcement.
Adaptable bacteria are more likely to be able to survive changes in their environment; they also pass those skills on to future generations. Those adaptations help biologists learn more about the biochemistry and molecular mechanisms of evolution.

To perform the study, Copley’s research team eliminated genes in Escherichia coli that code for critical enzymes. They then observed the bacteria reproducing over many generations to get a clear view of how the bacteria survived when given those limitations.

While the majority of enzymes have very specific functions that only work on one kind of chemical reaction, there are others that aren’t so specialized. These so-called ‘promiscuous’ enzymes might still be specific to one reaction but also have the ability to be flexible, boosting other reactions when conditions necessitate.
Pyridoxal phosphate (PLP, pyridoxal 5'-phosphate, P5P), the active form of vitamin B6 / Credit: Jynto and Ben Mills
The investigators found that new enzymes would fill in for missing ones in their E. coli. studies. For example, when an enzyme that helps make vitamin B6 is missing, the E. coli with that defect will turn to a new set of enzymes to produce the vitamin. Interestingly, those promiscuous enzymes don’t just substitute in for the ones that aren’t there. The replacements instead worked up an entirely new, often longer set of reactions to achieve the same result.

“We were rerouting metabolism,” explained Copley, a Professor of Molecular, Cellular and Developmental Biology at the University of Colorado Boulder.

A synthetic biologist at Harvard University, Betul Kacar, suggests that promiscuity could also give us a look into the past, showing us clues about what former roles and functions such enzymes may have had earlier in evolutionary history. An enzyme may be there to rescue the chemical reaction because catalyzing that reaction or one like it could have once been its primary job. “Trying to understand how novel pathways arise, what kind of mechanistic underlying forces shape those trajectories, is quite essential,” she explained.

Bacteria are able to formulate many kinds of alternative processes to make up for enzymes that are missing, depending on the environmental conditions they face, Copley noted. The most successful replacements are the efficient ones – reactions with fewer steps, or that can yield a larger amount of the necessary reaction product.

Sources: ScienceNews.org, 2nd American Society for Microbiology Conference on Experimental Microbial Evolution, University of Colorado Boulder
 
About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
JUL 04, 2018
Drug Discovery
JUL 04, 2018
Increased Dose of Drug 'Rifampin' Effective in Eliminating Tuberculosis Bacterium
According to a randomized controlled trial, a TB drug by the name ‘Rifampin’ was seen to effectively kill TB bacteria in sputum cultures when a...
JUL 19, 2018
Cardiology
JUL 19, 2018
HIV Infection Doubles Risk of Heart Disease
Recent study of 150 countries and over 800,000 people shows HIV patients are more than twice as likely to develop Heart Disease than uninfected individuals....
JUL 28, 2018
Videos
JUL 28, 2018
Separating Microbial Fact From Fiction
Can the toilet really send germs flying to your toothbrush?...
AUG 26, 2018
Videos
AUG 26, 2018
All About Extremophiles
Our planet hosts some very special microbes that live in some crazy places; they are called extremophiles....
SEP 29, 2018
Microbiology
SEP 29, 2018
In a First, Rat Variation of Hepatitis E Found in a Person
It was found in a 56-year-old Hong Kong man....
OCT 15, 2018
Microbiology
OCT 15, 2018
Surprising Source of Hospital-acquired Infections is Found
Is it a sick visitor, a dirty hospital gown, or the unwashed hands of a clinician? No, the infection is coming from inside the patient!...
Loading Comments...