麻豆传媒

TWO artificial DNA 鈥渓etters鈥� can link up just like the natural versions, paving the way for incorporating the newcomers into living cells.

Synthetic biologists are racing to come up with artificial versions of the building blocks of life. 鈥淲e have been basically reinventing the genetic alphabet from the bottom up,鈥� says of the Foundation for Applied Molecular Evolution in Alachua, Florida. Hopes for such fake DNA range from developing new drugs to creating artificial life.

In 2006, Benner and his colleagues , dubbed Z and P, which bond together to form a pair (ZP) in a similar way to the two natural DNA base pairs 鈥� AT and GC.

Shortly after, in 2008, a group led by at the Scripps Research Institute in La Jolla, California, built two more bases and showed that, just like DNA, natural enzymes could be used to replicate them. But their artificial base pairs were linked together into longer strands of DNA in a different way.

鈥淲hat we know about normal DNA is you have runs of the same base, AAAA or TTTT,鈥� says of Indiana University in Indianapolis. Because of the way they are joined together Romesberg鈥檚 bases can鈥檛 form such long runs.

Now Georgiadis and Benner have shown that their Z and P bases can form these runs, behaving just like natural DNA. Using X-ray crystallography they found that the bases could incorporate themselves into strands of both natural and unnatural bases that included runs of Z and P up to six bases long.

The researchers also showed that the strands took on the same two forms that normal DNA uses inside cells: the familiar helical structure, called the 鈥淏鈥� form, and a wider 鈥淎鈥� form that DNA adopts when it is binding with a protein ().

鈥淒NA normally has to adopt different forms to interact with different sets of proteins,鈥� Georgiadis says. 鈥淭he fact that Z and P can adopt these forms suggests that [DNA made with these bases] will behave in a cell like natural DNA.鈥� She says the ultimate goal is to 鈥渃reate new things鈥�.

聯The fact that Z and P can adopt two forms suggests they will behave like natural DNA聰

The work is impressive, says Romesberg. The ZP pair 鈥渃an really function like a GC or an AT鈥�, he says.

This article appeared in print under the headline 鈥淎rtificial DNA links up just like the real thing鈥�