Mutational analysis of the 3'-->5' proofreading exonuclease of Escherichia coli DNA polymerase III
نویسندگان
چکیده
منابع مشابه
Dysfunctional proofreading in the Escherichia coli DNA polymerase III core.
The epsilon-subunit contains the catalytic site for the 3'-->5' proofreading exonuclease that functions in the DNA pol III (DNA polymerase III) core to edit nucleotides misinserted by the alpha-subunit DNA pol. A novel mutagenesis strategy was used to identify 23 dnaQ alleles that exhibit a mutator phenotype in vivo. Fourteen of the epsilon mutants were purified, and these proteins exhibited 3'...
متن کاملProofreading by DNA polymerase III of Escherichia coli depends on cooperative interaction of the polymerase and exonuclease subunits.
The polymerase subunit (alpha) of Escherichia coli DNA polymerase III holoenzyme and the 3'----5' exonuclease subunit (epsilon) are each less active separately than together in the holoenzyme core (an assembly of alpha, epsilon, and theta subunits). In a complex formed from purified alpha and epsilon subunits, polymerase activity increased 2-fold, and that of the 3'----5' exonuclease increased ...
متن کاملAmino acid sequence motifs essential to 3'-->5' exonuclease activity of Escherichia coli DNA polymerase II.
Many DNA polymerases have conserved sequences required for 3'-->5' exonuclease activity, which contributes to the accuracy of DNA replication by removing misincorporated nucleotides prior to chain elongation. Using amino acid sequence alignments, we predicted the putative active site of the 3'-->5' exonuclease of Escherichia coli DNA polymerase II. Site-directed mutagenesis at D155A, E157A, D15...
متن کاملThe Subunit of Escherichia coli DNA Polymerase III: a Role in Stabilizing the ε Proofreading Subunit
The function of the subunit of Escherichia coli DNA polymerase III holoenzyme is not well established. is a tightly bound component of the DNA polymerase III core, which contains the subunit (polymerase), the subunit (3 35 exonuclease), and the subunit, in the linear order . Previous studies have shown that the subunit is not essential, as strains carrying a deletion of the holE gene (which enc...
متن کاملSpecificity and enzymatic mechanism of the editing exonuclease of Escherichia coli DNA polymerase III.
Exonucleolytic editing is a major contributor to the fidelity of DNA replication by the multisubunit DNA polymerase (pol) III holoenzyme. To investigate the source of editing specificity, we have studied the isolated exonuclease subunit, epsilon, and the pol III core subassembly, which carries the epsilon, theta, and alpha (polymerase) subunits. Using oligonucleotides with specific terminal mis...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nucleic Acids Research
سال: 1998
ISSN: 1362-4962
DOI: 10.1093/nar/26.17.4005