Global Regulators of


By jpeza - Posted on 21 Mayo 2009

Fecha Publicación: 
1 Ene 2008
Datos del paper
Autor Principal: 
David C. Grainger*
Volumen: 
65
Página Inicial: 
93
Página Final: 
113
Abstract: 

A. An overview of the bacterial multi-subunit RNApolymerase

In bacteria, RNA polymerase exists in two states. One form, known as the

core enzyme, can catalyze RNA synthesis 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 polymeras

e posses the rl2, ~ and W, and ú) subunits. The RNA polymerase

holoenzyme contains an additional subunit, a, and this is the subunit

that facilitates DNA recognition. Following a-mediated DNA binding,

transcription initiation occurs, the a 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 Escherichiacoli K-12 cells, which must be

distributed between ~3000 transcription units. Thus, the cell must 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 oí Biologieal Scienees, University oí Warwick, Coventry CV4 7AL, UK

t Sehool oí Bioscienees, University oí Birmingham, Edgbaston, Birmingham B15 2TI, United Kingdom

Keywords: 
RNA polymerase ; Escherichia coli
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