Open AccessTranscription regulation by inflexibility of promoter DNA in a looped complex.
Author(s) -
Hyon E. Choy,
S W Park,
Pradip K. Parrack,
Sankar Adhya
Publication year - 1995
Publication title -
proceedings of the national academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.92.16.7327
Subject(s) - promoter , dna , repressor , dna clamp , protein–dna interaction , transcription bubble , transcription (linguistics) , biology , hmg box , dna supercoil , microbiology and biotechnology , rna polymerase , genetics , chemistry , polymerase , dna replication , rna , dna binding protein , transcription factor , gene , rna dependent rna polymerase , reverse transcriptase , gene expression , linguistics , philosophy
The gal operon of Escherichia coli is negatively regulated by repressor binding to bipartite operators separated by 11 helical turns of DNA. Synergistic binding of repressor to separate sites on DNA results in looping, with the intervening DNA as a topologically closed domain containing the two promoters. A closed DNA loop of 11 helical turns, which is in-flexible to torsional changes, disables the promoters either by resisting DNA unwinding needed for open complex formation or by impeding the processive DNA contacts by an RNA polymerase in flux during transcription initiation. Interaction between two proteins bound to different sites on DNA modulating the activity of the intervening segment toward other proteins by allostery may be a common mechanism of regulation in DNA-multiprotein complexes.
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