Interaction of Escherichia coli σ70with Core RNA Polymerase
This extract was created in the absence of an abstract.
Excerpt
The RNA polymerase of Escherichia coli is a large,multisubunit enzyme existing in two forms. The core enzyme, consisting of subunits β and β′ and an α-subunitdimer (Burgess 1969a,b), carries out processive transcription elongation followed by termination. When oneof a variety of sigma (σ) factors is added to core, theholoenzyme is formed. The σ-subunit confers promoterspecific DNA binding and transcription initiation capabilities to the enzyme (Burgess and Travers 1970; Helmann and Chamberlin 1988; Gross et al. 1992, 1996). σ70of E. coli was the first σ factor to be described and characterized (Burgess et al. 1969). Since then, numerous σfactors have been discovered throughout the eubacterialkingdom, including six alternative σ factors in E. coli.Each σ directs transcription initiation from a specific setof promoters to transcribe genes usually with relatedfunctions. This control of transcription is mediated partially through the competition of the individual σ factorsfor the core enzyme and is a major part of global generegulation in bacteria (Zhou and Gross 1992). Elucidationof the structural characteristics of the core RNA polymerase σ factor-binding interaction will be very beneficial in fully understanding this aspect of regulation...
