New “Urzyme” Findings Challenge “RNA World” Assumptions on Origin of Life

Before there was life on Earth, there were molecules. A primordial soup. At some point a few specialized molecules began replicating. This self-replication, scientists agree, kick-started a biochemical process that would lead to the first organisms. But exactly how that happened — how those molecules began replicating — has been one of science's enduring mysteries. Now, research from University of North Carolina (UNC) School of Medicine biochemist Charles Carter, Ph.D., and colleagues, appearing in the September 13, 2013 issue of the Journal of Biological Chemistry, offers an intriguing new view on how life began. The paper was selected as one of the JBC’s papers of the week. Dr. Carter's work is based on lab experiments during which his team recreated ancient protein enzymes that likely played a vital role in helping create life on Earth. Dr. Carter's finding flies in the face of the widely-held theory that ribonucleic acid (RNA) self-replicated without the aid of simple proteins and eventually led to life as we know it. In the early 1980s, researchers found that ribozymes — RNA enzymes — act as catalysts. It was evidence that RNA can be both the blueprints and the chemical catalysts that put those blueprints into action. This finding led to the "RNA World" hypothesis, which posits that RNA alone triggered the rise of life from a sea of molecules. But for the hypothesis to be correct, ancient RNA catalysts would have had to copy multiple sets of RNA blueprints nearly as accurately as do modern-day enzymes. That's a hard sell; scientists calculate that it would take much longer than the age of the universe for randomly generated RNA molecules to evolve sufficiently to achieve the modern level of sophistication.
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