In a classic episode of an old television comedy called I Love Lucy, Lucille Ball enters a production line job in a candy factory. While the conveyor belt's speed exceeds its ability to package the candy, the rage brings out the best of it. She puts candy in her pockets, in her hat, in her mouth ̵
Faster means not always better. And precision can seriously affect the speed.
But sometimes innovative minds develop a new strategy that improves both efficiency and precision.
Two researchers from the University of Delaware have done so in two years of collaboration, which aims to improve a completely different assembly line process that could be helpful in the production of pharmaceuticals and biofuels.
Wilfred Chen, a professor of chemical engineering at Gore, and Emily Berckman, a doctoral candidate in the Department of Chemistry and Biochemistry, have published their new method in Chemical Communications a journal of the Royal Society of Chemistry.
The collaboration was accelerated by the Chemistry Biology Interface Program, which is sponsored by the National Institutes of Health and helps graduate students navigate concepts and methods from the chemical and biological sciences. The funding was also provided by the National Science Foundation.
The aim of her work was to develop a more efficient method for generating certain biochemical reactions in cells – in particular the way enzymes work together to promote these changes in the cells.
To understand this, imagine a relay team at a track meet, with one team member after another advancing the baton and passing it on to the finish line on the way to the finish line. Enzymes do some of their work in this way in cells. They act as catalysts to accelerate the reactions and to forward the new product to the next enzyme. In this case, the "batons" are the products of these reactions that change between each handover. Thus, enzyme # 1 modifies the rod and passes it to enzyme # 2, which modifies the rod and adds it to enzyme # 3, and so on, until the desired product is achieved.
"Imagine you want to" Pass one product on to the next person, "Chen said," but you're so far apart that it's difficult to pass it on. If you reduce the distance between the different partners, you will get better efficiency and accuracy and reduce competition. "
In nature, enzymes often cluster in groups to do something. This collaborative work in close proximity, in the protein-based Scaffolds serve as a collection point, creating a "cascade" of biochemical reactions.
Chen and Berckman have found an improved way to control the construction and placement of these scaffolds. CRISPR / Cas9 is an acronym (Clustered, Regular Interspaced Palindromic Repeats) describing DNA sequences used in the immune system of certain bacterial cells: When the bacterial cell is attacked by a virus, it cuts off and stores a portion of the viral DNA to recognize and assassinate the attacker on its next appearance
The process involves a protein called Cas9, which binds to the target seg ment of DNA and cuts it at this point. With this method, geneticists can now manipulate the genetic code to remove mutations that cause disease or other dysfunction.
Chen and Berckman do not handle genetic code with CRISPR. They use a modified form of Cas9 called dCas9, which does not have this scissor-like ability, but acts as a "superbinder". It sticks to each DNA target sequence and allows for precise placement of these enzyme scaffolds and their reaction cascade.
Chen has already used dCas9 for gene regulation and imaging applications. This is a new application.
Based on its work with RNA, the technique allows for an increased number of fusion points and a necessary unlocking mechanism called "toehold gRNA" that increases both precision and efficiency and predictability.
"We made a more precise assembly line," Berckman said. "We can turn it on, now we need to be able to turn it off, then you can finally apply it in as many ways as you can imagine – drugs, biofuels, cancer therapies."
CRISPR method for conditional gene regulation
Emily A. Berckman et al. Use of dCas9 fusion proteins for the dynamic assembly of synthetic metabolites, Chemical Communications (2019). DOI: 10.1039 / C9CC04002A
New variant of CRISPR technology (2019, 15 November)
retrieved on November 15, 2019
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