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Open access, freely available online Synopses of Research Articles The Ol’ Switcheroo Shows How an RNA Enzyme Splices Itself DOI: 10.1371/journal.pbio.0030310 Ribonucleic acid (RNA) is a dogma normal enzyme. Then, they replaced the breaker. The “central dogma” of oxygen in question with a sulfur atom. cellular biochemistry mandates that The reaction didn’t work as well because, deoxyribonucleic acid (DNA) stores by the rules of chemistry, sulfur doesn’t information, and RNA copies this like to bind to magnesium. But sulfur information and uses it to direct the does like manganese and cadmium assembly of amino acid building blocks ions. So they replaced the magnesium into proteins, such as enzymes. Enzymes with one of these other metal ions and catalyze important chemical reactions measured the reaction. The researchers in the cell, such as the breakdown of saw that these other metal ions restored glucose or the synthesis of urea. (or “rescued”) enzymatic activity. In short, When biochemists discovered catalytic the enzyme needs a bond where the RNA, they had to ditch the dogma. oxygen and the magnesium are, but the Because of its structure, it turns out, bond doesn’t have to be between oxygen RNA can act as an enzyme and catalyze and magnesium. DOI: 10.1371/journal.pbio.0030310.g001 reactions. While two strands of DNA As complicated as that is, plucking tend to zip up into the famous double out one atom and trading it for another RNA enzymes called ribozymes require helix,