P. Cysewski et R. Olinski, Ab initio quantum chemistry studies on the coding properties of cytosine derivatives generated by hydroxyl radical in aerobic conditions, J MOL ST-TH, 490, 1999, pp. 69-79
The coding properties of four free radicals derived cytosine modifications
were characterised by ab initio quantum chemistry method. The dimers geomet
ry was optimised without any restrictions. The analysis was focused on the
pairs consisting of a standard DNA base and one of the following cytosine d
erivatives: 5,6-dihydroxycytosine (1); 5,6-dihydroxyuracil (2); uracil glyc
ol (3); and isodialuric acid (4). The presented data allow to conclude that
all studied derivatives are able to form the most stable pairs with guanin
e. However, other pairs are also possible. In non-polar conditions the 5,6-
dihydroxycytosine (1) pair with cytosine in addition to a normal pairing wi
th guanine. This may stand for C double right arrow G transversion. The sig
nificant impact of the environment polarity on the dimers stabilisation ene
rgy was observed. The potential mispairing is enriched in the polar conditi
ons The 5,6-dihydroxyuracil (2) and isodialuric acid (4) may form stable pa
irs also with adenine. This may lead to C double right arrow T transition.
The mispairing of uracil glycol (3) was found as insignificant. (C) 1999 El
sevier Science B.V. All rights reserved.