During transcription initiation, RNA polymerases appear to retain promoter interactions while
transcribing short RNAs that are frequently released from the complex. Upon transition to
elongation, the polymerase releases promoter and forms a stable elongation complex. Little
is known about the changes in polymerase conformation or polymerase: DNA interactions
that occur during this process. To characterize the transitions that occur in the T7 RNA
polymerase transcription complex during initiation, we prepared enzymes with Fe-BABE …