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Versatile RNA Folds Into Two Ribozymes

For proteins, amino acid sequence determines structure, which in turn determines function. But catalytic RNAs don't necessarily play by the same rules, according to biology associate professor David P. Bartel and postdoctoral fellow Erik A Schultes of Massachusetts Institute of Technology and the Whitehead Institute for Biomedical Research. To prove their point, the researchers have constructed an RNA sequence that can fold two different ways, and each configuration has its own quite different catalytic activity [Science, 289,448 (2000)]. Compared with other ribozymes, the new sequence isn't a very good catalyst in either of its possible configurations. But the mere fact that it can take on two different shapes and functions at all upsets one of the canons of molecular biology. It time, ribozymes can evolve new capabilities without first acquiring mutations that change their RNA Bartel and Schultes study how, in the course of evolution, new RNA folds develop and ...