W. Wang et al., SECONDARY RADICAL ATTACK ON DNA NUCLEOTIDES - REACTION BY ADDITION TODNA BASES AND ABSTRACTION FROM SUGARS, International journal of radiation biology, 71(4), 1997, pp. 387-399
Citations number
61
Categorie Soggetti
Radiology,Nuclear Medicine & Medical Imaging","Nuclear Sciences & Tecnology
In this work radicals generated by dissociative electron attachment to
iodoacetamide (H2NCOCH2.) and 6-chloromethyluracil ((UCH2.)-C-6) are
suggested to react with DNA nucleotides in frozen aqueous solutions vi
a either hydrogen abstraction or addition to the double bonds of the b
ases. Methyl hydrogens of TMP are the preferential sites of the attack
by H2NCOCH2. radical. For dCMP the Cl' site on the sugar group is fou
nd to be the preferred site of hydrogen abstraction by H2NCOCH2. while
for dGMP and to a lesser extent dAMP attack al the C8 position of the
purine ring is found to be competitive with sugar attack. In general
allylic (UCH2.)-C-6 and (UCH2.)-C-5 radicals are found to be poor hydr
ogen abstractors and the only reaction pathway found is the addition t
o double bonds at C6 in thymine and C8 in adenine and guanine. Whereas
, the cytosine 5,6 double bond appears to be unreactive towards additi
on at low temperatures. Some evidence is found for sugar radical addit
ion to the adenine C8 position.