Site-specific cleavage of single-stranded DNAs at unique sites by a copper-dependent redox reaction.
Metal ions play a crucial role not only in the formation and maintenance of nucleic acid structure, but also in important biochemical conversions of polynucleotides. Some aqueous metal ions, acting as general acid/base (or electrophilic/nucleophilic) catalysts, can induce site-specific cleavage of RNA. DNA is not cleaved efficiently by the non-redox metal-induced mechanism. However, DNA degradation by radicals formed in the metal-catalysed auto-oxidation of ascorbate (or other reducing agents) is well known. In the past, the observed cleavage reactions have not been very specific. Here, we report a non-enzymatic cleavage of single-stranded DNA occurring at unique sites due to redox reactions involving copper. This could be considered a 'self-cleavage' reaction, by analogy with the lead-induced non-redox RNA cleavage reaction. This site-specific cleavage of DNA, stimulated by ascorbate and hydrogen peroxide, is most efficient under physiological conditions, so this phenomenon may have biological significance.
Kazakov
S A
SA
Institute of Bioorganic Chemistry, Siberian Division of the USSR Academy of Sciences, Novosibirsk.
Astashkina
T G
TG
Mamaev
S V
SV
Vlassov
V V
VV
D001205:Ascorbic Acid / Q000494:pharmacology; D001345:Autoradiography; D003300:Copper / Q000494:pharmacology*; D004277:DNA, Single-Stranded / Q000187:drug effects*; D004591:Electrophoresis, Polyacrylamide Gel; D006861:Hydrogen Peroxide / Q000494:pharmacology; D010084:Oxidation-Reduction; D013696:Temperature
D004277:DNA, Single-Stranded; D003300:Copper; D006861:Hydrogen Peroxide; D001205:Ascorbic Acid