Monovalent Copper and Silver Ions Block DNA Polymerase Chain Reaction

Abstract In the present study we present the dramatic effect that monovalent copper ions (Cu(I))have on the DNA polymerase chain reaction, and the moderate effect which monovalent silver ions (Ag(I)) have on it. Our research utilizes the commercial Polymerase Chain Reaction (PCR) system: in anaerobic conditions, in the presence of less than 0.1 mM of Cu(I) ions or in the presence of less than 10mM of Ag(I) ions, the PCR system was entirely shut down.Under the same conditions, 1 mM of divalent copper ions (Cu(II)) ions shows only a minor effect, while10mM of divalent Ni and Zn ions shows no effect at all.This finding can give some explanation for the strong antimicrobial activity of monovalent copper ions (Cu(I))as well as Ag(I). Although the mechanism of this effect is not yet fully understood, we recently published results showing that under the conditions of acidic pH, an unfavorable carbon source, low molecular oxygen concentration and elevated temperatures, the antibacterial action of Cu(I) ions is boosted, with a 106 bacterial population eliminated in less than 1 min by 0.4mM of Cu(I). Microscopy checking of E.coli morphology and light scattering testes showed mortality of bacteria with almost no lysis. These results suggest that rapid and lethal metabolic damage is the main mechanism of Cu(I)’s antimicrobial effect.