Sigma factor: Difference between revisions

The <scene name='59/591940/Transcription_bubble/1'>transcription bubble</scene> is fundamentally formed through the common '''housekeeping σ factors''' which unwind about 13 bp of duplex DNA in an ATP independent process.  As such, σ factors require invariant basic and aromatic residues (Phe, Tyr, Trp) critical for this formation.  The process of bubble formation begins at the -11 formation (usually A) and propogates to +1 site, through "base flipping" which interrupts the stacking interactions stabilizing the double helix conformation.  As a result, -35 and -10 motif sequence recognition and strand separation are both coupled by the σ factor.