Wednesday, April 9, 2008

Artificial Letters Added to Life's Alphabet

US researchers have created two artificial DNA bases, or 'letters', that can actually be accurately and efficiently replicated by a natural enzyme. Eventually, the researchers say, they may be able to add these two artificial building blocks to the four natural genetic bases that comprise DNA, opening up doors to widely different kinds of genetic engineering.

This unnatural but functioning new base pair is the result of nearly a decade of researcher by chemical biologist Floyd Romesberg, from the Scripps Reseach Institue, California, US.

Romesberg borrowed some tricks from drug development companies and, with the help of graduate student Aaron Leconte, used these to synthesis 3600 potential candidates for the artificial bases to see if they would be treated normally by a polymerase enzyme.Two different methods of screening both turned up the same pair of molecules, called dSICS and dMM02. A minor chemical alteration was made on the dSICS, due to its greater readiness to pair with itself rather than its intended partner, finally making an unnatural base pair, d5SICS and dMM02, that efficiently replicated without the need of an unnatural polymerase.

The molecular pair that worked surprised Romesberg. "We got it and said, 'Wow!' It would have been very difficult to have designed that pair rationally."

In the near future it is expected that these bases will be used to synthesize DNA with new and unnatural properties. These could include highly specific primers for DNA amplification; tags for materials, such as explosives, that could be detected without the risk of contamination from natural DNA; and building novel DNA-based nanomaterials.

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Blog post by Bethany Reid (41807444)

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