2.50
Hdl Handle:
http://hdl.handle.net/10541/109805
Title:
Interaction of copper(I) with nucleic acids.
Authors:
Prütz, W A; Butler, John; Land, Edward J
Abstract:
Poly(dG-dC) and poly(I) form particularly stable complexes with Cu(I): thus characteristic UV absorbance changes enabled demonstration of Cu(I) transfer from poly(dA-dT) to poly(dG-dC), or from DNA to poly(I). Using pulse radiolysis to generate Cu(I), a rate constant of approximately 4 x 10(7) dm3 mol-1 s-1 (per base unit) was estimated for association of Cu(I) to native DNA, and slightly higher values were found for poly(dA-dT), poly(C), poly(dG-dC) and poly(G). For native DNA and for the models poly(dA-dT) and poly(dG-dC) the addition of Cu(I) was followed by secondary absorbance changes in the time scale of 10 ms, probably due to internal Cu(I) transfer; such secondary reactions were not detectable in heat-denatured DNA or in the homopolymers of A, C, G, and I. Extraction of Cu(I) from the DNA by EDTA is slow, 0.019 s-1, and independent of EDTA concentration, indicating that dissociation of the DNA-Cu(I) complex is the rate-determining step. A tentative value can hence be given for the DNA-Cu(I) stability constant: K = k (forward)/k (reverse) approximately 2 x 10(9) dm3 mol-1. Addition of H2O2 to solutions of gamma-radiolytically generated DNA-Cu(I), at Cu(I)/base less than 0.01, resulted in DNA degradation, comparable in yield to .OH-induced degradation. In the case of poly(dA-dT) and poly(dG-dC) the reaction of H2O2 with the corresponding Cu(I) complexes produced even more damage than the reaction of .OH. The formation of DNA-Cu(I), and the deleterious reaction with H2O2, were hardly affected by RNase or BSA, when added at equal (w/v) concentration. Dismutation of O2.- by (Cu,Zn)-SOD was partly inhibited by DNA and even more by poly(I) at pH 4.4, but not at pH 7, probably by competitive complexation of Cu(I), occurring in the catalytic cycle of SOD.
Affiliation:
Institut für Biophysik und Strahlenbiologie, Universität Freiburg, FRG.
Citation:
Interaction of copper(I) with nucleic acids. 1990, 58 (2):215-34 Int. J. Radiat. Biol.
Journal:
International Journal of Radiation Biology
Issue Date:
Aug-1990
URI:
http://hdl.handle.net/10541/109805
DOI:
10.1080/09553009014551581
PubMed ID:
1974571
Type:
Article
Language:
en
ISSN:
0955-3002
Appears in Collections:
All Paterson Institute for Cancer Research

Full metadata record

DC FieldValue Language
dc.contributor.authorPrütz, W Aen
dc.contributor.authorButler, Johnen
dc.contributor.authorLand, Edward Jen
dc.date.accessioned2010-08-18T08:52:48Z-
dc.date.available2010-08-18T08:52:48Z-
dc.date.issued1990-08-
dc.identifier.citationInteraction of copper(I) with nucleic acids. 1990, 58 (2):215-34 Int. J. Radiat. Biol.en
dc.identifier.issn0955-3002-
dc.identifier.pmid1974571-
dc.identifier.doi10.1080/09553009014551581-
dc.identifier.urihttp://hdl.handle.net/10541/109805-
dc.description.abstractPoly(dG-dC) and poly(I) form particularly stable complexes with Cu(I): thus characteristic UV absorbance changes enabled demonstration of Cu(I) transfer from poly(dA-dT) to poly(dG-dC), or from DNA to poly(I). Using pulse radiolysis to generate Cu(I), a rate constant of approximately 4 x 10(7) dm3 mol-1 s-1 (per base unit) was estimated for association of Cu(I) to native DNA, and slightly higher values were found for poly(dA-dT), poly(C), poly(dG-dC) and poly(G). For native DNA and for the models poly(dA-dT) and poly(dG-dC) the addition of Cu(I) was followed by secondary absorbance changes in the time scale of 10 ms, probably due to internal Cu(I) transfer; such secondary reactions were not detectable in heat-denatured DNA or in the homopolymers of A, C, G, and I. Extraction of Cu(I) from the DNA by EDTA is slow, 0.019 s-1, and independent of EDTA concentration, indicating that dissociation of the DNA-Cu(I) complex is the rate-determining step. A tentative value can hence be given for the DNA-Cu(I) stability constant: K = k (forward)/k (reverse) approximately 2 x 10(9) dm3 mol-1. Addition of H2O2 to solutions of gamma-radiolytically generated DNA-Cu(I), at Cu(I)/base less than 0.01, resulted in DNA degradation, comparable in yield to .OH-induced degradation. In the case of poly(dA-dT) and poly(dG-dC) the reaction of H2O2 with the corresponding Cu(I) complexes produced even more damage than the reaction of .OH. The formation of DNA-Cu(I), and the deleterious reaction with H2O2, were hardly affected by RNase or BSA, when added at equal (w/v) concentration. Dismutation of O2.- by (Cu,Zn)-SOD was partly inhibited by DNA and even more by poly(I) at pH 4.4, but not at pH 7, probably by competitive complexation of Cu(I), occurring in the catalytic cycle of SOD.en
dc.language.isoenen
dc.subject.meshCopper-
dc.subject.meshDNA-
dc.subject.meshEdetic Acid-
dc.subject.meshHydrogen Peroxide-
dc.subject.meshHydroxides-
dc.subject.meshHydroxyl Radical-
dc.subject.meshKinetics-
dc.subject.meshSpectrophotometry, Ultraviolet-
dc.subject.meshSuperoxide Dismutase-
dc.titleInteraction of copper(I) with nucleic acids.en
dc.typeArticleen
dc.contributor.departmentInstitut für Biophysik und Strahlenbiologie, Universität Freiburg, FRG.en
dc.identifier.journalInternational Journal of Radiation Biologyen

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