Browse
Submit Data
Databases
API
Help

Dataset Information

10 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

T5 DNA polymerase: structural--functional relationships to other DNA polymerases.

ABSTRACT: T5 DNA polymerase, a highly processive single-polypeptide enzyme, has been analyzed for its primary structural features. The amino acid sequence of T5 DNA polymerase has a high degree of homology with that of DNA polymerase I from Escherichia coli and retains many of the amino acid residues that have been implicated in the 3'----5' exonuclease and DNA polymerase activities of that enzyme. Alignment with sequences of polymerase I and T7 DNA polymerase was used to identify regions possibly involved in the high processivity of this enzyme. Further, amino acid sequence comparisons of T5 DNA polymerase with a large group of DNA polymerases previously shown to exhibit little similarity to polymerase I indicate certain sequence segments are shared among distantly related DNA polymerases. These shared regions have been implicated in the 3'----5' exonuclease function of polymerase I, which suggests that the proofreading domains of all these enzymes may be evolutionarily related.

SUBMITTER: Leavitt MC

PROVIDER: S-EPMC287290 | biostudies-other | 1989 Jun

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Publications

T5 DNA polymerase: structural--functional relationships to other DNA polymerases.

Leavitt M C MC Ito J J

Proceedings of the National Academy of Sciences of the United States of America 19890601 12

T5 DNA polymerase, a highly processive single-polypeptide enzyme, has been analyzed for its primary structural features. The amino acid sequence of T5 DNA polymerase has a high degree of homology with that of DNA polymerase I from Escherichia coli and retains many of the amino acid residues that have been implicated in the 3'----5' exonuclease and DNA polymerase activities of that enzyme. Alignment with sequences of polymerase I and T7 DNA polymerase was used to identify regions possibly involve ...[more]

PMID: 2660138

Similar Datasets

Structure and function relationships in mammalian DNA polymerases.

Project description:DNA polymerases are vital for the synthesis of new DNA strands. Since the discovery of DNA polymerase I in Escherichia coli, a diverse library of mammalian DNA polymerases involved in DNA replication, DNA repair, antibody generation, and cell checkpoint signaling has emerged. While the unique functions of these DNA polymerases are differentiated by their association with accessory factors and/or the presence of distinctive catalytic domains, atomic resolution structures of DNA polymerases in complex with their DNA substrates have revealed mechanistic subtleties that contribute to their specialization. In this review, the structure and function of all 15 mammalian DNA polymerases from families B, Y, X, and A will be reviewed and discussed with special emphasis on the insights gleaned from recently published atomic resolution structures.

| S-EPMC7050493 | biostudies-literature

RNA aptamers selected against DNA polymerase beta inhibit the polymerase activities of DNA polymerases beta and kappa.

Project description:DNA polymerase beta (polbeta), a member of the X family of DNA polymerases, is the major polymerase in the base excision repair pathway. Using in vitro selection, we obtained RNA aptamers for polbeta from a variable pool of 8 x 10(12) individual RNA sequences containing 30 random nucleotides. A total of 60 individual clones selected after seven rounds were screened for the ability to inhibit polbeta activity. All of the inhibitory aptamers analyzed have a predicted tri-lobed structure. Gel mobility shift assays demonstrate that the aptamers can displace the DNA substrate from the polbeta active site. Inhibition by the aptamers is not polymerase specific; inhibitors of polbeta also inhibited DNA polymerase kappa, a Y-family DNA polymerase. However, the RNA aptamers did not inhibit the Klenow fragment of DNA polymerase I and only had a minor effect on RB69 DNA polymerase activity. Polbeta and kappa, despite sharing little sequence similarity and belonging to different DNA polymerase families, have similarly open active sites and relatively few interactions with their DNA substrates. This may allow the aptamers to bind and inhibit polymerase activity. RNA aptamers with inhibitory properties may be useful in modulating DNA polymerase activity in cells.

| S-EPMC1463896 | biostudies-literature

Structural diversity of the Y-family DNA polymerases.

Project description:The Y-family translesion DNA polymerases enable cells to tolerate many forms of DNA damage, yet these enzymes have the potential to create genetic mutations at high rates. Although this polymerase family was defined less than a decade ago, more than 90 structures have already been determined so far. These structures show that the individual family members bypass damage and replicate DNA with either error-free or mutagenic outcomes, depending on the polymerase, the lesion and the sequence context. Here, these structures are reviewed and implications for polymerase function are discussed.

| S-EPMC2846201 | biostudies-literature

PCNA mono-ubiquitination and activation of translesion DNA polymerases by DNA polymerase {alpha}.

Project description:Translesion DNA synthesis (TLS) involves PCNA mono-ubiquitination and TLS DNA polymerases (pols). Recent evidence has shown that the mono-ubiquitination is induced not only by DNA damage but also by other factors that induce stalling of the DNA replication fork. We studied the effect of spontaneous DNA replication errors on PCNA mono-ubiquitination and TLS induction. In the pol1L868F strain, which expressed an error-prone pol alpha, PCNA was spontaneously mono-ubiquitinated. Pol alpha L868F had a rate-limiting step at the extension from mismatched primer termini. Electron microscopic observation showed the accumulation of a single-stranded region at the DNA replication fork in yeast cells. For pol alpha errors, pol zeta participated in a generation of +1 frameshifts. Furthermore, in the pol1L868F strain, UV-induced mutations were lower than in the wild-type and a pol delta mutant strain (pol3-5DV), and deletion of the RAD30 gene (pol eta) suppressed this defect. These data suggest that nucleotide misincorporation by pol alpha induces exposure of single-stranded DNA, PCNA mono-ubiquitination and activates TLS pols.

| S-EPMC3892766 | biostudies-literature

Structural and functional analyses of the interaction of archaeal RNA polymerase with DNA.

Project description:Multi-subunit RNA polymerases (RNAPs) in all three domains of life share a common ancestry. The composition of the archaeal RNAP (aRNAP) is not identical between phyla and species, with subunits Rpo8 and Rpo13 found in restricted subsets of archaea. While Rpo8 has an ortholog, Rpb8, in the nuclear eukaryal RNAPs, Rpo13 lacks clear eukaryal orthologs. Here, we report crystal structures of the DNA-bound and free form of the aRNAP from Sulfolobus shibatae. Together with biochemical and biophysical analyses, these data show that Rpo13 C-terminus binds non-specifically to double-stranded DNA. These interactions map on our RNAP-DNA binary complex on the downstream DNA at the far end of the DNA entry channel. Our findings thus support Rpo13 as a RNAP-DNA stabilization factor, a role reminiscent of eukaryotic general transcriptional factors. The data further yield insight into the mechanisms and evolution of RNAP-DNA interaction.

| S-EPMC3479171 | biostudies-literature

Noncanonical prokaryotic X family DNA polymerases lack polymerase activity and act as exonucleases.

Project description:The X family polymerases (PolXs) are specialized DNA polymerases that are found in all domains of life. While the main representatives of eukaryotic PolXs, which have dedicated functions in DNA repair, were studied in much detail, the functions and diversity of prokaryotic PolXs have remained largely unexplored. Here, by combining a comprehensive bioinformatic analysis of prokaryotic PolXs and biochemical experiments involving selected recombinant enzymes, we reveal a previously unrecognized group of PolXs that seem to be lacking DNA polymerase activity. The noncanonical PolXs contain substitutions of the key catalytic residues and deletions in their polymerase and dNTP binding sites in the palm and fingers domains, but contain functional nuclease domains, similar to canonical PolXs. We demonstrate that representative noncanonical PolXs from the Deinococcus genus are indeed inactive as DNA polymerases but are highly efficient as 3'-5' exonucleases. We show that both canonical and noncanonical PolXs are often encoded together with the components of the non-homologous end joining pathway and may therefore participate in double-strand break repair, suggesting an evolutionary conservation of this PolX function. This is a remarkable example of polymerases that have lost their main polymerase activity, but retain accessory functions in DNA processing and repair.

| S-EPMC9226535 | biostudies-literature

An overview of Y-Family DNA polymerases and a case study of human DNA polymerase η.

Project description:Y-Family DNA polymerases specialize in translesion synthesis, bypassing damaged bases that would otherwise block the normal progression of replication forks. Y-Family polymerases have unique structural features that allow them to bind damaged DNA and use a modified template base to direct nucleotide incorporation. Each Y-Family polymerase is unique and has different preferences for lesions to bypass and for dNTPs to incorporate. Y-Family polymerases are also characterized by a low catalytic efficiency, a low processivity, and a low fidelity on normal DNA. Recruitment of these specialized polymerases to replication forks is therefore regulated. The catalytic center of the Y-Family polymerases is highly conserved and homologous to that of high-fidelity and high-processivity DNA replicases. In this review, structural differences between Y-Family and A- and B-Family polymerases are compared and correlated with their functional differences. A time-resolved X-ray crystallographic study of the DNA synthesis reaction catalyzed by the Y-Family DNA polymerase human polymerase η revealed transient elements that led to the nucleotidyl-transfer reaction.

| S-EPMC4018060 | biostudies-literature

Segregation of replicative DNA polymerases during S phase: DNA polymerase ?, but not DNA polymerases ?/?, are associated with lamins throughout S phase in human cells.

Project description:DNA polymerases (Pol) ?, ?, and ? replicate the bulk of chromosomal DNA in eukaryotic cells, Pol ? being the main leading strand and Pol ? the lagging strand DNA polymerase. By applying chromatin immunoprecipitation (ChIP) and quantitative PCR we found that at G(1)/S arrest, all three DNA polymerases were enriched with DNA containing the early firing lamin B2 origin of replication and, 2 h after release from the block, with DNA containing the origin at the upstream promoter region of the MCM4 gene. Pol ?, ?, and ? were released from these origins upon firing. All three DNA polymerases, Mcm3 and Cdc45, but not Orc2, still formed complexes in late S phase. Reciprocal ChIP of the three DNA polymerases revealed that at G(1)/S arrest and early in S phase, Pol ?, ?, and ? were associated with the same nucleoprotein complexes, whereas in late S phase Pol ? and Pol ?/? were largely associated with distinct complexes. At G(1)/S arrest, the replicative DNA polymerases were associated with lamins, but in late S phase only Pol ?, not Pol ?/?, remained associated with lamins. Consistently, Pol ?, but not Pol ?, was found in nuclear matrix fraction throughout the cell cycle. Therefore, Pol ? and Pol ?/? seem to pursue their functions at least in part independently in late S phase, either by physical uncoupling of lagging strand maturation from the fork progression, or by recruitment of Pol ?, but not Pol ?, to post-replicative processes such as translesion synthesis or post-replicative repair.

| S-EPMC3460436 | biostudies-other

Inhibition of mammalian DNA polymerases by resveratrol: mechanism and structural determinants.

Project description:Resveratrol, a natural compound found in many dietary plants and in red wine, plays an important role in the prevention of many human pathological processes, including inflammation, atherosclerosis and carcinogenesis. We have shown that the antiproliferative activity of resveratrol correlated with its ability to inhibit the replicative pols (DNA polymerases) alpha and delta in vitro [Stivala, Savio, Carafoli, Perucca, Bianchi, Maga, Forti, Pagnoni, Albini, Prosperi and Vannini (2001) J. Biol. Chem. 276, 22586-22594]. In this paper, we present the first detailed biochemical investigation on the mechanism of action of resveratrol towards mammalian pols. Our results suggest that specific structural determinants of the resveratrol molecule are responsible for selective inhibition of different mammalian pols, such as the family B pol alpha and the family X pol lambda. Moreover, the resveratrol derivative trans-3,5-dimethoxy-4-hydroxystilbene, which is endowed with a strong antiproliferative activity (Stivala et al., 2001), can inhibit pols alpha and lambda and also suppress the in vitro SV40 DNA replication. The potency of inhibition is similar to that of aphidicolin, an inhibitor of the three replicative pols alpha, delta and epsilon. Our findings establish the necessary background for the synthesis of resveratrol derivatives having more selective and potent antiproliferative activity.

| S-EPMC1175102 | biostudies-literature

Novel Escherichia coli RNA Polymerase Binding Protein Encoded by Bacteriophage T5.

Project description:The Escherichia coli bacteriophage T5 has three temporal classes of genes (pre-early, early, and late). All three classes are transcribed by host RNA polymerase (RNAP) containing the ?70 promoter specificity subunit. Molecular mechanisms responsible for the switching of viral transcription from one class to another remain unknown. Here, we find the product of T5 gene 026 (gpT5.026) in RNAP preparations purified from T5-infected cells and demonstrate in vitro its tight binding to E. coli RNAP. While proteins homologous to gpT5.026 are encoded by all T5-related phages, no similarities to proteins with known functions can be detected. GpT5.026 binds to two regions of the RNAP ? subunit and moderately inhibits RNAP interaction with the discriminator region of ?70-dependent promoters. A T5 mutant with disrupted gene 026 is viable, but the host cell lysis phase is prolongated and fewer virus particles are produced. During the mutant phage infection, the number of early transcripts increases, whereas the number of late transcripts decreases. We propose that gpT5.026 is part of the regulatory cascade that orchestrates a switch from early to late bacteriophage T5 transcription.

| S-EPMC7472727 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data