Global Regulators of Transcription in Escherichia coli: Mechanisms of Action and Methods for Study

By jpeza - Posted on 20 Octubre 2009

Fecha Publicación: 
1 Ene 2008
Datos del paper
Autor Principal: 
David C. Grainger*
Página Inicial: 
Página Final: 

A. An overview of the bacterial multi-subunit RNA polymerase
In bacteria, RNA polymerase exists in two states. One form, known as the
core enzyme, can catalyzeRNAsynthesis but is unable to bind to promoter
targets in DNA. The second form of RNA polymerase, the holoenzyme, is
capable of both RNA synthesis and promoter recognition. The bacterial
RNA polymerase is a multisubunit enzyme and both forms of RNA polymerase
posses the a2, b and b0, and o subunits. The RNA polymerase
holoenzyme contains an additional subunit, s, and this is the subunit
that facilitates DNA recognition. Following s-mediated DNA binding,
transcription initiation occurs, the s subunit then dissociates from the
RNA polymerase–DNA–mRNA complex and the core enzyme completes
the process of gene transcription. It is estimated that there are ~5000 copies
of RNA polymerase in growing Escherichia coli K-12 cells, which must be
distributed between ~3000 transcription units. Thus, the cellmust carefully
regulate the binding of RNA polymerase across its chromosome. RNA
polymerase activity can be modulated by DNA sequence elements, transcription
factors, nucleoid-associated proteins, small molecules, and RNA
polymerase binding proteins

Dirección del Autor: 

Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK
{ School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom

RNA polymerase ; core enzyme ; holoenzyme ; gene transcription

Stephen J. W. Busby

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