Apurinic endonuclease from <i>Saccharomyces cerevisiae</i>

Thielmann, Heinz Walter; Hess, Ulrich

doi:10.1042/bj1950407

Cited by 3 publications

(1 citation statement)

References 41 publications

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“…The primary role of the metal ion is to promote a conformational change in the DNA containing abasic site, priming it for enzyme-mediated hydrolysis [57]. Previous studies have demonstrated the importance of metal ions (Mg 2+ , Ca 2+ , Co 2+ , Zn 2+ and Mn 2+ ) for the activity of AP endonucleases across various species [55], [56], [57], [58], [59], [60], [61], [62]. The sequence alignment of mycobacterial AP endonucleases End and XthA with their homologues in Endonuclease IV and Exonuclease III family, reveals complete conservation of metal binding sites in End (His56, His96, Glu129, Asp162, His165, His191, Asp204, His206 and Glu233) and XthA (Asn32, Glu57, Asp180, Asn182 and His281) [63], [64].…”

Section: Discussionmentioning

confidence: 99%

Endonuclease IV Is the Major Apurinic/Apyrimidinic Endonuclease in Mycobacterium tuberculosis and Is Important for Protection against Oxidative Damage

et al. 2013

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During the establishment of an infection, bacterial pathogens encounter oxidative stress resulting in the production of DNA lesions. Majority of these lesions are repaired by base excision repair (BER) pathway. Amongst these, abasic sites are the most frequent lesions in DNA. Class II apurinic/apyrimidinic (AP) endonucleases play a major role in BER of damaged DNA comprising of abasic sites. Mycobacterium tuberculosis, a deadly pathogen, resides in the human macrophages and is continually subjected to oxidative assaults. We have characterized for the first time two AP endonucleases namely Endonuclease IV (End) and Exonuclease III (XthA) that perform distinct functions in M.tuberculosis. We demonstrate that M.tuberculosis End is a typical AP endonuclease while XthA is predominantly a 3′→5′ exonuclease. The AP endonuclease activity of End and XthA was stimulated by Mg2+ and Ca2+ and displayed a preferential recognition for abasic site paired opposite to a cytosine residue in DNA. Moreover, End exhibited metal ion independent 3′→5′ exonuclease activity while in the case of XthA this activity was metal ion dependent. We demonstrate that End is not only a more efficient AP endonuclease than XthA but it also represents the major AP endonuclease activity in M.tuberculosis and plays a crucial role in defense against oxidative stress.

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Section: Discussionmentioning

confidence: 99%

Endonuclease IV Is the Major Apurinic/Apyrimidinic Endonuclease in Mycobacterium tuberculosis and Is Important for Protection against Oxidative Damage

et al. 2013

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The cytotoxic action of activated and non-activated cyclophosphamide in yeast: Comparison of induced DNA damage

Fleer

Ruhland

Brendel

1982

Chemico-Biological Interactions

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DNA polymerase α from normal rat liver is different than DNA polymerases α from Morris hepatoma strains

Popanda

Thielmann

1989

European Journal of Biochemistry

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To investigate whether DNA replication in rat hepatoma cells is altered compared with that in normal rat liver, the main replicative enzyme, i.e. the DNA polymerase a complex, was partially purified from a slow-growing (TC5123) and a fast-growing (MH3924) Morris hepatoma cell strain as well as from normal rat liver. The purified DNA polymerase a complexes contained RNA primase. DNA polymerase a activities of these complexes were characterized with regard to both their molecular properties and their dNTP and DNA binding sites. The latter were probed with competitive inhibitors of dNTP binding, resulting in Ki values, and with DNA templates,The sedimentation coefficients of native DNA polymerases a from Morris hepatoma cells were found to be lower than that of polymerase a from normal rat liver. Consequently, when following the procedure of Siege1 and Monty for determination of molecular mass considerably smaller molecular masses were calculated for polyinerases of hepatoma strains (TC5123, 127 kDa; MH3924, 138 kDa; rat liver, 168 kDa). Similar differences were found when the dNTP binding site was probed with inhibitors. Ki values obtained with butylphenyl-dGTP were higher for polymerases of the hepatoma strains than for that of normal rat liver. However, Ki values measured with aphidicolin and butylanilino-dATP were lower for DNA polymerase a from the fast-growing hepatoma cell strain than for that from normal rat liver, indicating a reduced affinity of the dNTP binding sites for dATP and dCTP. This reduced affinity could be responsible for lowered specificity of nucleotide selection in the base-pairing process which in turn may cause an enhanced error rate in DNA replication in malignant cells. Furthermore, when the DNA binding site was characterized by Michaelis-Menten constants using gapped DNA as a template, K,,, values were similar for all three DNA polymerases. In contrast, the K,,, value measured with single-stranded DNA as a template was found to be lower for DNA polymerase a from the fast-growing hepatoma MH3924 than for that from normal rat liver. Thus, the DNA-polymerizing complex from MH3924 combines both higher binding strength to single-stranded DNA templates and decreased nucleotide selection, properties which may enhance replication velocity and may lower fidelity.DNA replication in eukaryotic cells is catalyzed by an enzyme complex which consists of a core activity, called DNA polymerase a, several associated proteins such as RNA primase, DNA helicase, DNA-binding proteins, and other polypeptides the function of which is as yet unknown [I]. This complex is able to replicate genomic DNA in bacteria with a rate of l o p 9 -lo-" misincorporations per base pair replicated [2]. From work on prokaryotes, we know that several mechanisms contribute to this degree of accuracy (see [3]). The main contribution originates from an associated 3'+5' exonuclease which removes mismatched nucleotides [4 -61. In eukaryotes, however, this enzyme is not a regular constituent of isolated polymerase a complexes, being ...

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Apurinic endonuclease from Saccharomyces cerevisiae

Cited by 3 publications

References 41 publications

Endonuclease IV Is the Major Apurinic/Apyrimidinic Endonuclease in Mycobacterium tuberculosis and Is Important for Protection against Oxidative Damage

Endonuclease IV Is the Major Apurinic/Apyrimidinic Endonuclease in Mycobacterium tuberculosis and Is Important for Protection against Oxidative Damage

The cytotoxic action of activated and non-activated cyclophosphamide in yeast: Comparison of induced DNA damage

DNA polymerase α from normal rat liver is different than DNA polymerases α from Morris hepatoma strains

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