scholarly journals Deoxynucleotide Triphosphate Binding Mode Conserved in Y Family DNA Polymerases

2003 ◽  
Vol 23 (8) ◽  
pp. 3008-3012 ◽  
Author(s):  
Robert E. Johnson ◽  
José Trincao ◽  
Aneel K. Aggarwal ◽  
Satya Prakash ◽  
Louise Prakash
Keyword(s):  
Dna Polymerase ◽  
Close Contact ◽  
Dna Polymerases ◽  
Binding Mode ◽  
Nucleotide Incorporation ◽  
The Family ◽  
And Function ◽  
High Degree ◽  
Y Family ◽  
Deoxynucleotide Triphosphate

ABSTRACT Although DNA polymerase η (Polη) and other Y family polymerases differ in sequence and function from classical DNA polymerases, they all share a similar right-handed architecture with the palm, fingers, and thumb domains. Here, we examine the role in Saccharomyces cerevisiae Polη of three conserved residues, tyrosine 64, arginine 67, and lysine 279, which come into close contact with the triphosphate moiety of the incoming nucleotide, in nucleotide incorporation. We find that mutational alteration of these residues reduces the efficiency of correct nucleotide incorporation very considerably. The high degree of conservation of these residues among the various Y family DNA polymerases suggests that these residues are also crucial for nucleotide incorporation in the other members of the family. Furthermore, we note that tyrosine 64 and arginine 67 are functionally equivalent to the deoxynucleotide triphosphate binding residues arginine 518 and histidine 506 in T7 DNA polymerase, respectively.

scholarly journals MsDpo4—a DinB Homolog fromMycobacterium smegmatis—Is an Error-Prone DNA Polymerase That Can Promote G:T and T:G Mismatches

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Amit Sharma ◽  
Deepak T. Nair
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Polymerase ◽  
Environmental Conditions ◽  
Mycobacterium Smegmatis ◽  
Molecular Level ◽  
Dna Polymerases ◽  
Adaptive Mutagenesis ◽  
E Coli ◽  
Nucleotide Incorporation ◽  
Y Family

Error-prone DNA synthesis in prokaryotes imparts plasticity to the genome to allow for evolution in unfavorable environmental conditions, and this phenomenon is termed adaptive mutagenesis. At a molecular level, adaptive mutagenesis is mediated by upregulating the expression of specialized error-prone DNA polymerases that generally belong to the Y-family, such as the polypeptide product of thedinBgene in case ofE. coli. However, unlikeE. coli, it has been seen that expression of the homologs ofdinBinMycobacterium tuberculosisare not upregulated under conditions of stress. These studies suggest that DinB homologs inMycobacteriamight not be able to promote mismatches and participate in adaptive mutagenesis. We show that a representative homolog fromMycobacterium smegmatis(MsDpo4) can carry out template-dependent nucleotide incorporation and therefore is a DNA polymerase. In addition, it is seen that MsDpo4 is also capable of misincorporation with a significant ability to promote G:T and T:G mismatches. The frequency of misincorporation for these two mismatches is similar to that exhibited by archaeal and prokaryotic homologs. Overall, our data show that MsDpo4 has the capacity to facilitate transition mutations and can potentially impart plasticity to the genome.

The Inscriptions on the Gravestones in the Croatian Villages of Slovakia, Chunovo and Jarovce: The Specificity of Mixing Graphics Systems

2019 ◽  
Vol 14 (1-2) ◽  
pp. 159-173
Author(s):  
Darya Yu. Vashchenko
Keyword(s):  
Foreign Language ◽  
Ethnic Group ◽  
Ethnic Groups ◽  
Native Language ◽  
Close Contact ◽  
Funerary Monuments ◽  
Traditional Spelling ◽  
The Family ◽  
High Degree ◽  
The Village

The article discusses the inscriptions on funerary monuments from the Croatian villages of Cunovo and Jarovce, located in the South of Slovakia, near Bratislava. These inscriptions reflect the complicated sociocultural situation in the region, which is particularly specific due to the fact that this territory was included to Slovakia’s territory only after 1946, while earlier the village was part of Hungary. In addition, the local Croatian ethnic group was actively in close contact with the German and Hungarian communities. At the same time, the orthographic norms of the literary Croatian, German, Hungarian, and Slovak languages, which could potentially be owned by the authors of the inscriptions, differ in many ways, despite the Latin alphabet used on all the gravestones. All this is reflected in the tombstones, representing a high degree of mixing codes. The article identifies the main types of fusion on the monuments: separate orthograms, writing the maiden name of the deceased in the spelling of her native language, the traditional spelling of the family name. In addition, the mixing of codes can be associated with writing feminitives, also order of name and surname within the anthroponym. Moreover, the settlements themselves represent different ethnic groups coexistence within the village. Gravestones from the respective cemeteries also differ from each other in the nature of the prevailing trend of the mixing codes. In Jarovce, where the ethnic groups live compactly, fusion is often presented as a separate foreign language orthograms. In Cunovo, where the ethnic groups constitute a global conglomerate, more traditional presents for a specific family spelling of the names on the monument.

scholarly journals The Spacious Active Site of a Y-Family DNA Polymerase Facilitates Promiscuous Nucleotide Incorporation Opposite a Bulky Carcinogen-DNA Adduct

2004 ◽  
Vol 279 (35) ◽  
pp. 36951-36961 ◽  
Author(s):  
Rebecca A. Perlow-Poehnelt ◽  
Ilya Likhterov ◽  
David A. Scicchitano ◽  
Nicholas E. Geacintov ◽  
Suse Broyde
Keyword(s):  
Dna Polymerase ◽  
Active Site ◽  
Dna Adduct ◽  
Nucleotide Incorporation ◽  
Y Family

scholarly journals DNA Polymerase and dRP-lyase activities of polymorphic variants of human Pol ι

2021 ◽  
Vol 478 (7) ◽  
pp. 1399-1412
Author(s):  
Evgeniy S. Shilkin ◽  
Anastasia S. Gromova ◽  
Margarita P. Smal ◽  
Alena V. Makarova
Keyword(s):  
Dna Damage ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
Altered Expression ◽  
Dna Polymerase Iota ◽  
Nucleotide Incorporation ◽  
Lyase Activity ◽  
Polymorphic Variants ◽  
Y Family

Y-family DNA polymerase iota (Pol ι) is involved in DNA damage response and tolerance. Mutations and altered expression level of POLI gene are linked to a higher incidence of cancer. We biochemically characterized five active site polymorphic variants of human Pol ι: R71G (rs3218778), P118L (rs554252419), I236M (rs3218784), E251K (rs3218783) and P365R (rs200852409). We analyzed fidelity of nucleotide incorporation on undamaged DNA, efficiency and accuracy of DNA damage bypass, as well as 5′-deoxyribophosphate lyase (dRP-lyase) activity. The I236M and P118L variants were indistinguishable from the wild-type Pol ι in activity. The E251K and P365R substitutions altered the spectrum of nucleotide incorporation opposite several undamaged DNA bases. The P365R variant also reduced the dRP-lyase activity and possessed the decreased TLS activity opposite 8-oxo-G. The R71G mutation dramatically affected the catalytic activities of Pol ι. The reduced DNA polymerase activity of the R71G variant correlated with an enhanced fidelity of nucleotide incorporation on undamaged DNA, altered lesion-bypass activity and reduced dRP-lyase activity. Therefore, this amino acid substitution likely alters Pol ι functions in vivo.

scholarly journals Efficient and Error-Free Replication past a Minor-Groove N2-Guanine Adduct by the Sequential Action of Yeast Rev1 and DNA Polymerase ζ

2004 ◽  
Vol 24 (16) ◽  
pp. 6900-6906 ◽  
Author(s):  
M. Todd Washington ◽  
Irina G. Minko ◽  
Robert E. Johnson ◽  
Lajos Haracska ◽  
Thomas M. Harris ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Close Contact ◽  
Dna Polymerases ◽  
Minor Groove ◽  
Synthetic Activity ◽  
Oxidation Reactions ◽  
Lesion Bypass ◽  
Dna Minor Groove

ABSTRACT Rev1, a member of the Y family of DNA polymerases, functions in lesion bypass together with DNA polymerase ζ (Polζ). Rev1 is a highly specialized enzyme in that it incorporates only a C opposite template G. While Rev1 plays an indispensable structural role in Polζ-dependent lesion bypass, the role of its DNA synthetic activity in lesion bypass has remained unclear. Since interactions of DNA polymerases with the DNA minor groove contribute to the nearly equivalent efficiencies and fidelities of nucleotide incorporation opposite each of the four template bases, here we examine the possibility that unlike other DNA polymerases, Rev1 does not come into close contact with the minor groove of the incipient base pair, and that enables it to incorporate a C opposite the N 2-adducted guanines in DNA. To test this idea, we examined whether Rev1 could incorporate a C opposite the γ-hydroxy-1,N 2-propano-2′deoxyguanosine DNA minor-groove adduct, which is formed from the reaction of acrolein with the N 2 of guanine. Acrolein, an α,β-unsaturated aldehyde, is generated in vivo as the end product of lipid peroxidation and from other oxidation reactions. We show here that Rev1 efficiently incorporates a C opposite this adduct from which Polζ subsequently extends, thereby completing the lesion bypass reaction. Based upon these observations, we suggest that an important role of the Rev1 DNA synthetic activity in lesion bypass is to incorporate a C opposite the various N 2-guanine DNA minor-groove adducts that form in DNA.

scholarly journals yeast killer plasmid pGKL1 encodes a DNA polymerase belonging to the family B DNA polymerases

1987 ◽  
Vol 15 (21) ◽  
pp. 9088-9088 ◽  
Author(s):  
Guhung Jung ◽  
Mark C. Leavitt ◽  
Junetsu Ito
Keyword(s):  
Dna Polymerase ◽  
Dna Polymerases ◽  
The Family ◽  
Killer Plasmid ◽  
Yeast Killer

scholarly journals Composition and Function of Telomerase—A Polymerase Associated with the Origin of Eukaryotes

Biomolecules ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1425
Author(s):  
Petra Procházková Schrumpfová ◽  
Jiří Fajkus
Keyword(s):  
Dna Polymerase ◽  
Dna Polymerases ◽  
Telomerase Activity ◽  
Structural Features ◽  
Enzyme Complex ◽  
Eukaryotic Evolution ◽  
Linear Chromosomes ◽  
And Function ◽  
Phylogenetic Divergence ◽  
Origin Of Eukaryotes

The canonical DNA polymerases involved in the replication of the genome are unable to fully replicate the physical ends of linear chromosomes, called telomeres. Chromosomal termini thus become shortened in each cell cycle. The maintenance of telomeres requires telomerase—a specific RNA-dependent DNA polymerase enzyme complex that carries its own RNA template and adds telomeric repeats to the ends of chromosomes using a reverse transcription mechanism. Both core subunits of telomerase—its catalytic telomerase reverse transcriptase (TERT) subunit and telomerase RNA (TR) component—were identified in quick succession in Tetrahymena more than 30 years ago. Since then, both telomerase subunits have been described in various organisms including yeasts, mammals, birds, reptiles and fish. Despite the fact that telomerase activity in plants was described 25 years ago and the TERT subunit four years later, a genuine plant TR has only recently been identified by our group. In this review, we focus on the structure, composition and function of telomerases. In addition, we discuss the origin and phylogenetic divergence of this unique RNA-dependent DNA polymerase as a witness of early eukaryotic evolution. Specifically, we discuss the latest information regarding the recently discovered TR component in plants, its conservation and its structural features.

scholarly journals Pre-Steady-State Kinetic Analysis of the Incorporation of Anti-HIV Nucleotide Analogs Catalyzed by Human X- and Y-Family DNA Polymerases

2010 ◽  
Vol 55 (1) ◽  
pp. 276-283 ◽  
Author(s):  
Jessica A. Brown ◽  
Lindsey R. Pack ◽  
Jason D. Fowler ◽  
Zucai Suo
Keyword(s):  
Mitochondrial Dna ◽  
Steady State ◽  
Substrate Specificity ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Steady State Kinetic ◽  
Y Family ◽  
State Kinetic

ABSTRACTNucleoside reverse transcriptase inhibitors (NRTIs) are an important class of antiviral drugs used to manage infections by human immunodeficiency virus, which causes AIDS. Unfortunately, these drugs cause unwanted side effects, and the molecular basis of NRTI toxicity is not fully understood. Putative routes of NRTI toxicity include the inhibition of human nuclear and mitochondrial DNA polymerases. A strong correlation between mitochondrial toxicity and NRTI incorporation catalyzed by human mitochondrial DNA polymerase has been established bothin vitroandin vivo. However, it remains to be determined whether NRTIs are substrates for the recently discovered human X- and Y-family DNA polymerases, which participate in DNA repair and DNA lesion bypassin vivo. Using pre-steady-state kinetic techniques, we measured the substrate specificity constants for human DNA polymerases β, λ, η, ι, κ, and Rev1 incorporating the active, 5′-phosphorylated forms of tenofovir, lamivudine, emtricitabine, and zidovudine. For the six enzymes, all of the drug analogs were incorporated less efficiently (40- to >110,000-fold) than the corresponding natural nucleotides, usually due to a weaker binding affinity and a slower rate of incorporation for the incoming nucleotide analog. In general, the 5′-triphosphate forms of lamivudine and zidovudine were better substrates than emtricitabine and tenofovir for the six human enzymes, although the substrate specificity profile depended on the DNA polymerase. Our kinetic results suggest NRTI insertion catalyzed by human X- and Y-family DNA polymerases is a potential mechanism of NRTI drug toxicity, and we have established a structure-function relationship for designing improved NRTIs.

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