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The β clamp targets DNA polymerase IV to DNA and strongly increases its processivity
Author(s) -
Wagner Jérôme,
Fujii Shingo,
Gruz Petr,
Nohmi Takehiko,
Fuchs Robert P P
Publication year - 2000
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1093/embo-reports/kvd109
Subject(s) - processivity , dna clamp , dna polymerase , dna polymerase ii , polymerase , clamp , dna , dna polymerase i , biology , biophysics , microbiology and biotechnology , genetics , polymerase chain reaction , chemistry , gene , reverse transcriptase , computer science , clamping , computer vision
The recent discovery of a new family of ubiquitous DNA polymerases involved in translesion synthesis has shed new light onto the biochemical basis of mutagenesis. Among these polymerases, the dinB gene product (Pol IV) is involved in mutagenesis in Escherichia coli . We show here that the activity of native Pol IV is drastically modified upon interaction with the β subunit, the processivity factor of DNA Pol III. In the absence of the β subunit Pol IV is strictly distributive and no stable complex between Pol IV and DNA could be detected. In contrast, the β clamp allows Pol IV to form a stable initiation complex ( t 1/2 ≈ 2.3 min), which leads to a dramatic increase in the processivity of Pol IV reaching an average of 300–400 nucleotides. In vivo , the β processivity subunit may target DNA Pol IV to its substrate, generating synthesis tracks much longer than previously thought.