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PDBsum entry 5inl
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Hydrolase/DNA
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PDB id
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5inl
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References listed in PDB file
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Key reference
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Title
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Reversal of DNA damage induced topoisomerase 2 DNA-Protein crosslinks by tdp2.
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Authors
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M.J.Schellenberg,
L.Perera,
C.N.Strom,
C.A.Waters,
B.Monian,
C.D.Appel,
C.K.Vilas,
J.G.Williams,
D.A.Ramsden,
R.S.Williams.
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Ref.
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Nucleic Acids Res, 2016,
44,
3829-3844.
[DOI no: ]
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PubMed id
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Abstract
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Mammalian Tyrosyl-DNA phosphodiesterase 2 (Tdp2) reverses Topoisomerase 2 (Top2)
DNA-protein crosslinks triggered by Top2 engagement of DNA damage or poisoning
by anticancer drugs. Tdp2 deficiencies are linked to neurological disease and
cellular sensitivity to Top2 poisons. Herein, we report X-ray crystal structures
of ligand-free Tdp2 and Tdp2-DNA complexes with alkylated and abasic DNA that
unveil a dynamic Tdp2 active site lid and deep substrate binding trench
well-suited for engaging the diverse DNA damage triggers of abortive Top2
reactions. Modeling of a proposed Tdp2 reaction coordinate, combined with
mutagenesis and biochemical studies support a single Mg(2+)-ion mechanism
assisted by a phosphotyrosyl-arginine cation-π interface. We further identify a
Tdp2 active site SNP that ablates Tdp2 Mg(2+) binding and catalytic activity,
impairs Tdp2 mediated NHEJ of tyrosine blocked termini, and renders cells
sensitive to the anticancer agent etoposide. Collectively, our results provide a
structural mechanism for Tdp2 engagement of heterogeneous DNA damage that causes
Top2 poisoning, and indicate that evaluation of Tdp2 status may be an important
personalized medicine biomarker informing on individual sensitivities to
chemotherapeutic Top2 poisons.
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