19-Jul-2019 - American Chemical Society (ACS)

'Semi-synthetic' bacteria churn out unnatural proteins

Synthetic biologists seek to create new life with forms and functions not seen in nature. Although scientists are a long way from making a completely artificial life form, they have made semi-synthetic organisms that have an expanded genetic code, allowing them to produce never-before-seen proteins. Now, researchers reporting in Journal of the American Chemical Society have optimized a semi-synthetic bacteria to efficiently produce proteins containing unnatural amino acids.

All of Earth's natural life forms store information using a four-letter genetic code consisting of the nucleotides deoxyadenosine (dA), deoxyguanosine (dG), deoxycytidine (dC), and deoxythymidine (dT). Within the DNA double helix, dA pairs with dT, and dG with dC, to form the "rungs" of the DNA ladder. Recently, researchers have made synthetic nucleotides that can pair up with each other. When they placed these unnatural nucleotides into genes, bacteria could replicate the DNA and convert the sequences into RNA and then proteins that contained unconventional amino acids. However, bacteria often cannot use these synthetic sequences as efficiently as the natural ones. Therefore, Lingjun Li, Floyd Romesberg and colleagues wanted to optimize the unnatural base pairs to improve protein production.

The researchers tested different combinations of unnatural base pairs in E. coli and observed which ones were replicated most efficiently and produced the highest levels of a protein. Some of the synthetic base pairs had been tested before, whereas others were new variations. The team then used these optimized base pairs to demonstrate, for the first time, a semi-synthetic organism that could make a protein containing multiple unnatural amino acids.

Facts, background information, dossiers
  • amino acids
  • nucleotides
  • proteins
  • bacteria
More about American Chemical Society
  • News

    Superheroes, foods and apps bring a modern twist to the periodic table

    Many students, especially non-science majors, dread chemistry. The first lesson in an introductory chemistry course typically deals with how to interpret the periodic table of elements, but its complexity can be overwhelming to students with little or no previous exposure. Now, researchers ... more

    Luminescent wood could light up homes of the future

    The right indoor lighting can help set the mood, from a soft romantic glow to bright, stimulating colors. But some materials used for lighting, such as plastics, are not eco-friendly. Now, researchers reporting in ACS Nano have developed a bio-based, luminescent, water-resistant wood film t ... more

    Gold- and bronze-like paints that don't contain metal

    Lustrous metallic paints are used to enhance the beauty of many products, such as home decorations, cars and artwork. But most of these pigments owe their sheen to flakes of aluminum, copper, zinc or other metals, which have drawbacks. Now, researchers reporting in ACS Omega have developed ... more

  • Videos

    What Makes Rubber Rubbery?

    Reactions is looking at sports science today. Sports balls owe their reliability to an unusual polymer. Learn about the chemistry of rubber the all-star’s best friend! more

    Dragon's Blood Could Save Your Life

    This week Reactions is looking at chemistry in bizarre places that could save your life. The science within the blood of the Komodo dragon or in a horseshoe crab can help with antibiotic resistance. But it doesn't end there, so we're taking a closer look at other wild places in nature that ... more

    Why is Olive Oil Awesome?

    Whether you sop it up with bread or use it to boost your cooking, olive oil is awesome. But a lot of chemistry goes on in that bottle that can make or break a product. Take the “extra virgin” standard: Chemistry tells us that a higher free-fatty-acid content leads to a lower grade, less tas ... more

More about Scripps Research Institute