DNA-BINDING AND PHOTOCLEAVAGE BY URANYL(VI) (UO2(2+)) SALTS

• The interaction of the uranyl(VI) ion (UO22+) with DNA and its light-induced cleavage of DNA has been studied using flow-linear dichroism and P-32-endlabeled oligonucleotides. It was found that binding of uranyl ion to DNA is a prerequisite for photocleavage; from run-off experiments the binding constant was estimated to be of the order of 10(10) M-1 at pH 4. The angular orientation of the [O=U=O]2+ chromophore is consistent with binding by bridging phosphate groups on opposite strands of the minor groove of DNA; at higher DNA concentration aggregation indicates intermolecular bridging as well. The uranyl-mediated photocleavage of DNA is not influenced by the presence of O2, is more efficient at low pH (

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

reduced dichroism curves

dichroism

mechanisms

linear

1

contacts

degradation

release

identification

nuclease activity

10-phenanthroline copper-ion

complex

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