RNA polymerase Promote DNA S. 3510 Polymerase binds loosely to the consensus sequences and forms a closed complex. 3 DNA 5 3510 Polymerase then binds more tightly and the DNA is unwound near the -10 region to form the open complex. Synthesis of RNA begins. DNA 3 5 Purine nucleotide≈ Template strand triphosphate ⊙1 DNA sH The o subunit is released as polymerase proceeds beyond the promoter