The Escherichia coli DNA polymerase III holoenzyme contains both products of the dnaX gene, tau and gamma, but only tau is essential
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چکیده
منابع مشابه
DNA polymerase III holoenzyme of Escherichia coli.
DNA polymerase III holoenzyme has been purified from Escherichia coli HMS-83, using, as an assay, the conversion of coliphage G4 single-stranded DNA to the duplex replicative form. The holoenzyme consists of at least four different subunits: a, /I, y, and 6 of 140,000, 40,000, 52,000, and 32,000 daltons, respectively. The (Y subunit is DNA polymerase III, the dnaE gene product. The holoenzyme h...
متن کاملThe gamma subunit of DNA polymerase III holoenzyme of Escherichia coli is produced by ribosomal frameshifting.
The tau and gamma subunits of DNA polymerase III holoenzyme are both products of the dnaX gene. Since tau and gamma are required as stoichiometric components of the replicative complex, a mechanism must exist for the cell to coordinate their synthesis and ensure that both subunits are present in an adequate quantity and ratio for assembly. We have proposed that gamma is produced by a translatio...
متن کاملThe DNA polymerase III holoenzyme contains γ and is not a trimeric polymerase.
There is widespread agreement that the clamp loader of the Escherichia coli replicase has the composition DnaX3δδ'χψ. Two DnaX proteins exist in E. coli, full length τ and a truncated γ that is created by ribosomal frameshifting. τ binds DNA polymerase III tightly; γ does not. There is a controversy as to whether or not DNA polymerase III holoenzyme (Pol III HE) contains γ. A three-τ form of Po...
متن کاملReconstitution of a minimal DNA replicase from Pseudomonas aeruginosa and stimulation by non-cognate auxiliary factors.
DNA polymerase III holoenzyme is responsible for chromosomal replication in bacteria. The components and functions of Escherichia coli DNA polymerase III holoenzyme have been studied extensively. Here, we report the reconstitution of replicase activity by essential components of DNA polymerase holoenzyme from the pathogen Pseudomonas aeruginosa. We have expressed and purified the processivity f...
متن کاملChromosomal replicases as asymmetric dimers: studies of subunit arrangement and functional consequences.
Studies of the DNA polymerase III holoenzyme of Escherichia coli support a model in which both the leading and lagging strand polymerases are held together in a complex with the replicative helicase and priming activities, allowing two identical alpha catalytic subunits to assume different functions on the two strands of the replication fork. Creation of distinct functions for each of the two p...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1993
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.175.18.6018-6027.1993