Number of base pairs of promoter DNA that are unwound to form a so-called “transcription bubble”

Range ~15 Base pairs
Organism Eukaryotes
Reference Liu X, Bushnell DA, Kornberg RD. RNA polymerase II transcription: structure and mechanism. Biochim Biophys Acta. 2013 Jan1829(1):2-8. doi: 10.1016/j.bbagrm.2012.09.003. p.2 right column top paragraphPubMed ID23000482
Comments P.2 left column bottom paragraph:"A key transformation of the PIC [a giant preinitiation complex] is from a “closed” promoter complex, in which the DNA is entirely double stranded, to an “open” promoter complex, in which some 15 base pairs (bp) of the promoter DNA are unwound to form a so-called “transcription bubble.” Subsequent events include transcription start site (TSS) selection, de novo RNA synthesis (formation of the first phosphodiester bond), abortive initiation, and promoter escape." See Malinen et al. 2012 PMID 22570421 p.7442 left column bottom paragraph:"Transcribing RNAPs do not displace the non-template strand, but rather form a transient 9–10 bp RNA–DNA hybrid within the 11–12 bp melted DNA bubble."
Entered by Uri M
ID 111570