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).