Model: RNA polymerase

• Binds promoter
• Begins transcription while retaining upstream promoter contacts
• Maintains upstream contacts through the synthesis of an 8 base RNA
• Releases promoter contacts on translocation from +8 through to +10
• Begins to release initial RNA on translocation from +10 to +11
  • Heteroduplex reaches a maximal length of 10 base pairs!
  • (it soon contracts do about 7-8 base pairs during elongation).