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Biochemical Characterization of an Exonuclease from Arabidopsis thaliana Reveals Similarities to the DNA Exonuclease of the Human Werner Syndrome Protein

Plchova, H.; Hartung, F.; Puchta, H.

The human Werner syndrome protein (hWRN-p) possessing DNA helicase and exonuclease activities is essential for genome stability. Plants have no homologue of this bifunctional protein, but surprisingly the Arabidopsis genome contains a small open reading frame (ORF) (AtWRNexo) with homology to the exonuclease domain of hWRN-p. Expression of this ORF in Escherichia coli revealed an exonuclease activity for AtWRNexo-p with similarities but also some significant differences to hWRN-p. The protein digests recessed strands of DNA duplexes in the 3' -> 5' direction but hardly single-stranded DNA or blunt-ended duplexes. In contrast to the Werner exonuclease, AtWRNexo-p is also able to digest 3'-protruding strands. DNA with recessed 3'-PO4 and 3'-OH termini is degraded to a similar extent. AtWRNexo-p hydrolyzes the 3'-recessed strand termini of duplexes containing mismatched bases. AtWRNexo-p needs the divalent cation Mg$^{2+}$ for activity, which can be replaced by Mn$^{2+}$. Apurinic sites, cholesterol adducts, and oxidative DNA damage (such as 8-oxoadenine and 8-oxoguanine) inhibit or block the enzyme. Other DNA modifications, including uracil, hypoxanthine and ethenoadenine, did not inhibit AtWRNexo-p. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000016534
Veröffentlicht am 31.03.2020
DOI: 10.1074/jbc.M303891200
Zitationen: 24
Web of Science
Zitationen: 22
Zugehörige Institution(en) am KIT Botanisches Institut und Botanischer Garten (BOTANIK)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2003
Sprache Englisch
Identifikator ISSN: 0021-9258, 1083-351X
KITopen-ID: 1000016534
Erschienen in The journal of biological chemistry
Verlag American Society for Biochemistry and Molecular Biology
Band 278
Seiten 44128-44138
Nachgewiesen in PubMed
Web of Science
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