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ISSN
1672-9145
Acta Biochim Biophys Sin
2005, 37(1): 39–46
CN 31-1940/Q
Raman Spectroscopic Analysis of the Effect of Ultraviolet
Irradiation on Calf Thymus DNA
Yu-Long TANG and Zhou-Yi GUO*
Institute of Laser and Life Science, South China Normal University, Guangzhou
510631, China
Abstract Raman spectroscopy was
used for the first time to detect the effect of independent UVA (ultraviolet-A:
320–400 nm) and UVB (ultraviolet-B: 280–320 nm) irradiation on the calf thymus DNA
in aqueous solution. After both UVA and UVB irradiation for 1 h or 3 h, the
damage to the conformation of DNA was moderate, but the reduction of the B-form
DNA component was obvious. Both UVA and UVB caused significant damage to the
deoxyribose moiety and bases, among which the pyrimidine base pairs were more
seriously affected. There appeared to be preferential damaging sites on DNA
molecules caused by UVA and UVB irradiation. UVA irradiation caused more damage
to the deoxyribose than UVB irradiation, while UVB irradiation caused more
significant damage to the pyrimidine moiety than UVA irradiation. After UVB
irradiation for 3 h, unstacking of the AT base pairs and the cytosine ring took
place, severe damage to the thymine moiety occurred, and some base pairs were
modified. Moreover, with either UVA or UVB irradiation for 3 h, the
photoreactivation of DNA occurred. The damage to the DNA caused by UVB was
immediate, while the damage caused by UVA was proportional to the irradiation
duration. The experimental results partly indicate the formation of some
cyclobutane pyrimidine dimers and (6-4) photoproducts.
Key words Raman spectroscopy;
deoxyribonucleic acid (DNA); ultraviolet irradiation (UV); base pair
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Received: September 9, 2004 Accepted: December 10,
2004
This work was supported by the grants from the Key Science and
Technology Project of the National Ministry of Education (No. 02113) and the
Natural Science Foundation Project of Guangdong Province (No. 015012, No.
031518)
*Corresponding author: Tel, 86-20-85214758; Fax, 86-20-85216052;
E-mail, [email protected]