DNA unwinding produced by site-specific intrastrand cross-links of the antitumor drug cis-diamminedichloroplatinum(II)

Journal Article · Tue Aug 13 00:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00246a021· OSTI ID:5822568

Bellon, S F; Coleman, J H; Lippard, S J ^[1]

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1. Massachusetts Inst. of Tech., Cambridge (United States)

The DNA unwinding produced by specific adducts of the antitumor drug cis-diamminedi-chloroplatinum(II) has been quantitatively determined. Synthetic DNA duplex oligonucleotides of varying lengths with two base pair cohesive ends were synthesized and characterized that contained site-specific intrastrand N7-purine/N7-purine cross-links. Included are cis-(Pt(NH{sub 3}){sub 2}(d(GpG))), cis-(Pt(NH){sub 3}{sub 2}(d(ApG))), and cis-(Pt(NH{sub 3}){sub 2}(d(GpTpG))) adducts, respectively referred to as cis-GG, cis-AG, and cis-GTG. Local DNA distortions at the site of platination were amplified by polymerization of these monomers and quantitatively evaluated by using polyacrylamide gel electrophoresis. The extent of DNA unwinding was determined by systematically varying the interplatinum distance, or phasing, in polymers containing the adducts. The multimer that migrates most slowly gives the optimal phasing for cooperative bending, from which the degree of unwinding can be obtained. The authors find that the cis-GG and cis-AG adducts both unwind DNA by 13{degrees}, while the cis-GTG adduct unwinds DNA by 23{degrees}. In addition, experiments are presented that support previous studies revealing that a hinge joint forms at the sites of platination in DNA molecules containing trans-GTG adducts. On the basis of an analysis of the present and other published studies of site-specifically modified DNA. The authors propose that local duplex unwinding is a major determinant in the recognition of DNA damage by the Escherichia coli (A)BC excinuclease. In addition, local duplex unwinding of 13{degrees} and bending by 35{degrees} are shown to correlate well with the recognition of platinated DNA by a previously identified damage recognition protein (DRP) in human cells.

• OSTI ID: 5822568
• Journal Information: Biochemistry; (United States), Vol. 30:32; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
DNA
CROSS-LINKING
OLIGONUCLEOTIDES
AUTORADIOGRAPHY
PLATINUM COMPLEXES
GENETIC EFFECTS
ANTINEOPLASTIC DRUGS
DNA ADDUCTS
ELECTROPHORESIS
ESCHERICHIA COLI
PHOSPHORUS 32
ADDUCTS
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
CHEMICAL REACTIONS
COMPLEXES
DAYS LIVING RADIOISOTOPES
DRUGS
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS ISOTOPES
POLYMERIZATION
RADIOISOTOPES
TRANSITION ELEMENT COMPLEXES
550200* - Biochemistry