1qda | pdb_00001qda

Crystal structure of epidoxorubicin-formaldehyde virtual crosslink of DNA

spinqualitylabelsall models 1qda, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1qda is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.6Å Ligands: DM6, G49 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Epidoxorubicin and daunorubicin are proposed to be cytotoxic to tumor cells by catalyzing production of formaldehyde through redox cycling and using the formaldehyde for covalent attachment to DNA at G bases. The crystal structure of epidoxorubicin covalently bound to a d(CGCGCG) oligomer was determined to 1.6 A resolution. The structure reveals slightly distorted B-form DNA bearing two molecules of epidoxorubicin symmetrically intercalated at the termini, with each covalently attached from its N3' to N2 of a G base via a CH2 group from the formaldehyde. The structure is analogous to daunorubicin covalently bound to d(CGCGCG) determined previously, except for additional hydrogen bonding from the epimeric O4' to O2 of a C base. The role of drug-DNA covalent bonding in cells was investigated with synthetic epidoxorubicin-formaldehyde conjugate (Epidoxoform) and synthetic daunorubicin-formaldehyde conjugate (Daunoform). Uptake and location of drug fluorophore in doxorubicin-resistant human breast-cancer cells (MCF-7/ADR cells) was observed by fluorescence microscopy and flow cytometry. The fluorophore of Daunoform appeared more rapidly in cells and was released more rapidly from cells than the fluorophore of Epidoxoform over a 3 h exposure period. The fluorophore appeared predominantly in the nucleus of cells treated with both conjugates. The difference in uptake is explained in terms of the slower rate of hydrolysis of Epidoxoform to the species reactive with DNA and a proposed slower release from DNA based upon the crystal structures. Crystal structure of epidoxorubicin-formaldehyde virtual crosslink of DNA and evidence for its formation in human breast-cancer cells.,Podell ER, Harrington DJ, Taatjes DJ, Koch TH Acta Crystallogr D Biol Crystallogr. 1999 Sep;55(Pt 9):1516-23. PMID:10489446 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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