Nobel Laureate Finds 'Elegant' Explanation For DNA Transcribing Enzyme's High Fidelity

Roger Kornberg won the Nobel Prize in Chemistry for his efforts to unravel the molecular basis of eukaryotic transcription, in which enzymes give 'voice' to DNA by copying it into the RNA molecules that serve as templates for protein in organisms from yeast to humans. Now, Kornberg and his colleagues report new structures that reveal another critical piece of the puzzle: how the so-called polymerase II enzyme discriminates among potential RNA building blocks to ensure the characteristic accuracy of the process. The researchers found that a portion of the enzyme known as the trigger loop acts like a 'trap door,' swinging beneath a matching nucleoside triphosphate (NTP) building block, to close off the active center and form an extensive network of interactions with the NTP and other parts of the enzyme.