Strange behavior of bacteria with artificial proteins

(anxc.tv) - An approach to understanding the components of living organisms is to try to create them, using the principles of chemistry, engineering and genetics. A set of powerful techniques - collectively called synthetic biology - has been used to produce self-replicating molecules, artificial pathways in living systems and organisms that carry synthetic genes.

John Chaput, a researcher at the Institute of Biodesign Institute of Arizona State University and colleagues at the Department of Pharmacy, Midwestern University, Glendale, AZ, has built an artificial protein in Laboratory and test ways in which living cells respond to this artificial protein.

"If you take a protein that was created in a test tube and put it inside the cell, it still works," Chaput asked. "Does the cell recognize it? Does the cell just" chew "and eliminate it ? " This undiscovered area represents a new domain for synthetic biology and can eventually lead to the development of novel therapeutic agents.

The research results, presented online in the Journal of Biochemistry (ACS Chemical Biology), describe a particularly adaptive trend of Escherichia coli bacterial cells when exposed to a synthetic protein, which is Name it DX. Inside the cell, DX proteins bind to ATP molecules. ATP is an energy source that all biological entities need.

"ATP is the energy flow of life , " Chaput said. ATP provides energy for reactions in the living system, releasing energy when these bonds break down chemically. The depletion of ATP present in cells by DX interferes with normal metabolic activity in cells, preventing cell division, (although cells continue to grow).

Escherichia coli bacteria

After exposure to DX, normal bacteria of E. coli spheres develop into long fibers. During the period of these bacteria are filamentous, dense lipid structures in the active cell to partition the cells at regular intervals along its length. Unusual structures, which the authors call endoliposomes , are an unprecedented phenomenon in those cells.

"Somewhere along this microbial fiber, other processes began to occur that we did not fully understand at the genetic level, but we could see the results shown in phenotype ," Chaput. "The dense lipid structures are forming in very stable areas along the cell fiber and it seems to be a protective mechanism, allowing cells to separate themselves . " This particular response has never been observed in bacterial cells and appears only with a single-celled organism.

Producing a synthetic protein like DX, which mimics the complex folding characteristics of natural proteins and attaches to an important metabolite like ATP, is not an easy task, Chaput explains. A clever strategy called mRNA sequence is used to produce, regulate and amplify synthetic proteins capable of binding ATP with high affinity and specificity.

First, sets of random sequence peptides are formed from four DNA nucleic acids, each consisting of about 80 nucleotides. The chains are then copied into RNA with the help of an enzyme - RNA polymerase. If a natural ribosome is then introduced, it binds the strands and reads random RNA as if it were an RNA in nature, producing a synthetic protein when it moves along the chain. In this way, synthetic proteins based on random RNA sequences can be generated.

In this study, DX-exposed E. coli cells converted into a microfiber form. Cells show low metabolism and limit cell division, perhaps due to their ATP deficiency.

The study also tested the resiliency of E. coli after DX attachment. The cells return to their non-fibrous state after 48 hours, but they lose fertility. Moreover, this condition is difficult to reverse and seems to involve cell reprogramming.

Research shows that there is still a lot to learn about bacterial behavior and their reactions when cells encounter novel situations such as an unfamiliar synthetic protein. This study also noted that many infectious agents rely on an inactive state to avoid detection by antibiotics. A better understanding of these behavioral mechanisms may provide a new approach to targeting such pathogens.