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1
Content available remote

Template-directed base pairing of 2-chloro-2'-deoxyadenosine catalyzed by AMV reverse transcriptase

100%
Bukowska-Maciejewska A. M., Kuśmierek J. T.
Acta Biochimica Polonica
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1998
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vol. 45
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issue 2
587-593
2
Content available remote

Bacterial DNA repair genes and their eukaryotic homologues: 2. Role of bacterial mutator gene homologues in human disease. Overview of nucleotide pool sanitization and mismatch repair systems

100%
Arczewska K. D., Kuśmierek J. T.
|
2007
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vol. 54
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issue 3
435-457
EN
Since the discovery of the first E. coli mutator gene, mutT, most of the mutations inducing elevated spontaneous mutation rates could be clearly attributed to defects in DNA repair. MutT turned out to be a pyrophosphohydrolase hydrolyzing 8-oxodGTP, thus preventing its incorporation into DNA and suppresing the occurrence of spontaneous AT→CG transversions. Most of the bacterial mutator genes appeared to be evolutionarily conserved, and scientists were continuously searching for contribution of DNA repair deficiency in human diseases, especially carcinogenesis. Yet a human MutT homologue - hMTH1 protein - was found to be overexpressed rather than inactivated in many human diseases, including cancer. The interest in DNA repair contribution to human diseases exploded with the observation that germline mutations in mismatch repair (MMR) genes predispose to hereditary non-polyposis colorectal cancer (HNPCC). Despite our continuously growing knowledge about DNA repair we still do not fully understand how the mutator phenotype contributes to specific forms of human diseases.
3
Content available remote

Miscoding properties of isoguanine (2-oxoadenine) studied in an AMV reverse transcriptase in vitro system

100%
Bukowska A. M., Kuśmierek J. T.
Acta Biochimica Polonica
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1996
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vol. 43
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issue 1
247-254
4
Content available remote

Practical highly enantioselective synthesis of (R)- and (S)-(E)-4-hydroxynon-2-enal

81%
Komisarski M., Kaczmarska Z., Kuśmierek J. T.
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|
issue 1
189-193
EN
Oxidative stress enhances lipid peroxidation (LPO) implicated in cancer promotion and progression. (E)-4-Hydroxynon-2-enal 1 (trans-4-hydroxy-2-nonenal, HNE) is one of the most abundant products of LPO. Reactions of HNE with DNA and proteins are responsible for its mutagenic and toxic effects. On the other hand, HNE is regarded as a key molecule in stress mediated cell cycle signaling. LPO generates racemic HNE (rac-1); however, it is expected that the individual enantiomers will behave differently in their interactions with cell components. The study of HNE stereochemistry in its chemical and biochemical interactions is hindered by the lack of expedient methods for preparation of pure enantiomers. This study presents one step synthesis of HNE in a cross-metathesis reaction between the commercially available oct-1-en-3-ol and acrolein in the presence of 2nd generation Grubbs catalyst. The use in the metathesis reaction of enantiomers of oct-1-en-3-ol obtained via Candida antarctica lipase resolution of the racemate allowed us to prepare of 4-(R)- and 4-(S)-enantiomers of HNE (R-1 and S-1, respectively) with excellent optical purity (97.5 and 98.4% ee, respectively) and good chemical yields (70%).
5
Content available remote

Endogenous and exogenous DNA lesions recognized by N-alkylpurine-DNA glycosylases

70%
Borys E., Kuśmierek J. T.
Acta Biochimica Polonica
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1998
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vol. 45
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issue 2
579-586
6
Content available remote

Mismatch dependent uracil/thymine-DNA glycosylases excise exocyclic hydroxyethano and hydroxypropano cytosine adducts.

61%
Borys-Brzywczy E., Arczewska K. D., Saparbaev M., Hardeland U., Schär P., Kuśmierek J. T.
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2005
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vol. 52
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issue 1
149-165
EN
Exocyclic adducts of DNA bases, such as etheno- and hydroxyalkano- ones, are generated by a variety of bifunctional agents, including endogenously formed products of lipid peroxidation. In this work we selectively modified cytosines in the 5'-d(TTT TTT CTT TTT CTT TTT CTT TTT T)-3' oligonucleotide using: chloroacetaldehyde to obtain 3,N4-α-hydroxyethano- (HEC) and 3,N4-etheno- (εC), acrolein to obtain 3,N4-α-hydroxypropano- (HPC) and crotonaldehyde to obtain 3,N4-α-hydroxy-γ-methylpropano- (mHPC) adducts of cytosine. The studied adducts are alkali-labile which results in oligonucleotide strain breaks at the sites of modification upon strong base treatment. The oligonucleotides carrying adducted cytosines were studied as substrates of Escherichia coli Mug, human TDG and fission yeast Thp1p glycosylases. All the adducts studied are excised by bacterial Mug although with various efficiency: εC >HEC >HPC >mHPC. The yeast enzyme excises efficiently εC ł HEC >HPC, whereas the human enzyme excises only εC. The pH-dependence curves of excision of εC, HEC and HPC by Mug are bell shaped and the most efficient excision of adducts occurs within the pH range of 8.6-9.6. The observed increase of excision of HEC and HPC above pH 7.2 can be explained by deprotonation of these adducts, which are high pKa compounds and exist in a protonated form at neutrality. On the other hand, since εC is in a neutral form in the pH range studied, we postulate an involvement of an additional catalytic factor. We hypothesize that the enzyme structure undergoes a pH-induced rearrangement allowing the participation of Lys68 of Mug in catalysis via a hydrogen bond interaction of its ε-amino group with N4 of the cytosine exocyclic adducts.
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