FIZIKA A 11 (2002) 4 , 131-138

LASER DIRECT BIPHOTONIC PHOTOLYSIS OF GUANINES WITHIN DNA

Z. SHAQIRI^a, A. VESELI^b, N. SHAQIRI^c, E. VIDOLOVA-ANGELOVA^a and D. ANGELOV^a

^aInstitute of Solid State Physics, Bulgarian Academy of Sciences,
Tzargradsko Chaussee blvd. 72, BG-1784, Sofia, Bulgaria
Faculty of Natural and Mathematical Sciences, 38000, Prishtina, Kosovo
^cAcademy of Medicine blvd. 1, G. Sofiski, Sofia, Bulgaria

Received 20 April 2001; revised manuscript received 23 January 2003
Accepted 27 January 2003    Online 07 February 2003

Nanosecond laser-induced oxidative lesions at guanines within DNA were investigated using sequencing gel electrophoresis analysis. Strong sequence-specific lesions on guanines were revealed by either Fpg or piperidine treatments and assigned to 8-oxoG and oxazolone, respectively. It was shown that both the biphotonic ionization process and the chemical reactivity of the radical cation (G⁺) are dependent on the DNA sequence. The former were explained by the occurrence of energy and charge migration phenomena, while the latter in terms of local DNA hydration peculiarities.

PACS numbers: 87.14.Gg, 87.15.Mi
UDC 539.199, 539.196

Keywords: Fpg, piperidine, laser photolysis, 8-oxoG, oxazolone, guanine radical, energy and charge transfer in DNA

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