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DNA: Expanding code of life with new 'letters'

Date:
May 27, 2015
Source:
American Chemical Society
Summary:
The DNA encoding all life on Earth is made of four building blocks called nucleotides, commonly known as 'letters,' that line up in pairs and twist into a double helix. Now, two groups of scientists are reporting for the first time that two new nucleotides can do the same thing -- raising the possibility that entirely new proteins could be created for medical uses.
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Scientists have created a double helix out of six nucleotides, two more than what nature had devised.
Credit: American Chemical Society

The DNA encoding all life on Earth is made of four building blocks called nucleotides, commonly known as "letters," that line up in pairs and twist into a double helix. Now, two groups of scientists are reporting for the first time that two new nucleotides can do the same thing -- raising the possibility that entirely new proteins could be created for medical uses.

Their two studies appear in ACS' Journal of the American Chemical Society.

Synthetic biologists have been attempting for years to expand on nature's genetic "alphabet," consisting of the nucleotide bases cytosine, guanine, adenine and thymine -- also represented by the letters "C," "G," "A" and "T," respectively. But so far, the potential additions they've tested have shown limited promise. For example, one duo pairs up but doesn't form a nice helix, an important criterion given that the bases would have to incorporate fairly seamlessly with the original four to be useful. Millie M. Georgiadis, Steven A. Benner and colleagues from Indiana and Florida wanted to see if another potential set of letters, "Z" (6-amino-5-nitro-2(1H)-pyridone) and "P" (2-amino-imidazo[1,2-a]-1,3,5-triazin-4(8H)one), would form a helix -- and evolve.

The researchers found that multiple Z-P pairs can contribute to a double helix, just as C-G and A-T pairs do, with the same combination of flexibility and rigidity required for natural DNA to function. They also showed that the Z-P pairs integrate well with conventional pairs and that six-letter GACTZP DNA can evolve. The evolution of DNA containing the new building blocks endows the structures with new properties that could be useful in protein recognition.


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Materials provided by American Chemical Society. Note: Content may be edited for style and length.


Journal Reference:

  1. Millie M. Georgiadis, Isha Singh, Whitney F. Kellett, Shuichi Hoshika, Steven A. Benner, Nigel G. J. Richards. Structural Basis for a Six Nucleotide Genetic Alphabet. Journal of the American Chemical Society, 2015; 150519090051005 DOI: 10.1021/jacs.5b03482

Cite This Page:

American Chemical Society. "DNA: Expanding code of life with new 'letters'." ScienceDaily. ScienceDaily, 27 May 2015. <www.sciencedaily.com/releases/2015/05/150527113101.htm>.
American Chemical Society. (2015, May 27). DNA: Expanding code of life with new 'letters'. ScienceDaily. Retrieved May 25, 2017 from www.sciencedaily.com/releases/2015/05/150527113101.htm
American Chemical Society. "DNA: Expanding code of life with new 'letters'." ScienceDaily. www.sciencedaily.com/releases/2015/05/150527113101.htm (accessed May 25, 2017).

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