Researchers Re-Engineer E-Coli DNA to Make it Programmable
A team of synthetic biologists led by Farren Isaacs at Yale University [has taken] Escherichia coli cells and replaced all of the UAG stop codons with UAAs. They also deleted the instructions for making the release factor that usually binds to UAG, effectively rendering UAG meaningless…
The next step was to assign a new meaning to UAG during protein production. The team did this by designing molecules called transfer RNAs and accompanying enzymes that would attach an unnatural amino acid – fed to the cell – wherever they spotted the UAG codon…
By reintroducing UAGs at specific locations, as the Yale team have done, unnatural amino acids can be added into proteins at will.
"We now have an organism that has a new code, and we can reliably and efficiently open up the chemical diversity of proteins," says Isaacs.
For example, artificial amino acids could be added that give proteins unusual properties, such as the ability to bind to metals – resulting in novel adhesives. Or enzymes could be developed that are activated only in the presence of other molecules – which could be useful for drugs. “The genetic code is conserved for all of life, so this is a fundamental step forward,” says Philipp Holliger of the MRC Laboratory of Molecular Biology in Cambridge, UK. He says that because so much of the genetic code is redundant, there might be other codons that could be reassigned to expand the chemistry of living organisms.
The ‘Soap Bubble Nebula’ was discovered by an amateur astronomer, Dave Jurasevich, on July 6th, 2008. Officially known as PN G75.5+1.7, this image was taken by the Kitt Peak Mayall 4-metre telescope in 2009.
The image is a combination of two filters, ionised hydrogen (H-alpha) in orange and ionised oxygen (OIII) in blue.
The Soap Bubble was not discovered until recently due to it being embedded in a diffuse nebula (seen as the extended hydrogen component of the image), as well as its intrinsic faintness.
The distinct spherical symmetry is rare, making it very similar to Abell 39 which we wrote about earlier.
Image: T. A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOAO/AURA/NSF
More Information: 1, 2, 3
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