This discovery supports the hypothesis of an RNA world in which RNA molecules were among the earliest catalysts of life. This idea is based in part on the observation that RNA still retains many of its catalytic capabilities, including the ability to make proteins. Gradually, according to this theory, proteins began taking over some of the original functions of RNA.

"The most ancient (protein) molecules were involved in the interconversion of nucleotides. But they were not synthesizing them," Caetano-Anolls said. "We see that all the enzymes that were involved in purine synthesis, for example, were very recent. Since these first proteins benefited the formation of building blocks for the primitive RNA world, it makes a lot of sense that we've found this origin encased in nucleotide metabolism."

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Contact: Diana Yates
diya@uiuc.edu
217-333-5802
University of Illinois at Urbana-Champaign
18-May-2007