Core RNA polymerase from E-coli induces a major change in the domain arrangement of the sigma(70) subunit

Luminescence resonance energy transfer measurements were used to show that binding of E. coli core RNA polymerase induced major changes in interdomain distances in the sigma(70) subunit. The simplest model describing core-ind uced changes in sigma(70) involves a movement of the conserved region 1 by similar to 20 Angstrom and the conserved region 4.2 by similar to 15 Angstr om with respect to conserved region 2. The core-induced movement of region 1 (autoinhibition domain) and region 4.2 (DNA-binding domain) provides stru ctural rationale for allosteric regulation of sigma(70) DNA binding propert ies by the core and suggests that this regulation may not only involve dire ctly the autoinhibition domain of sigma(70) but also could involve a modula tion of spacing between DNA-binding domains of sigma(70) induced by binding of core RNAP.