Yeast RNA polymerase has grooves that could be binding sites for nucleic acids. The pink beads show a possible path for DNA that is -25A wide and 5 10A deep. The green beads show a narrower channel, 12-15A wide and -20A deep, that could hold RNA Photograph kindly provided by roger KornbergYeast RNA polymerase has grooves that could be binding sites for nucleic acids.The pink beads show a possible path for DNA that is ~25Å wide and 5- 10Å deep.The green beads show a narrower channel,12-15Å wide and ~20Å deep,that could hold RNA.Photograph kindly provided by Roger Kornberg