UV-absorbing substance in the red alga Porphyra yezoensis (Bangiales, Rhodophyta) block thymine photodimer production.
The effect of the water-soluble UV-absorbing substance (UVAS) extracted from the marine red alga Porphyra yezoensis Ueda on UV-dependent thymine photodimer production was investigated. The T<>T pyrimidine-pyrimidone 6-4 dimer and the cyclobutane cis-syn T<>T 5-6 dimer produced by UV irradiation with a xenon lamp were analyzed by reverse-phase high-performance liquid chromatography. Although the dimer production was reduced when the irradiation was filtered through a UVAS solution, it decreased more when thymine was mixed with UVAS. Furthermore, UVAS inhibited the degradation of UV-irradiated thymine. The inhibitory effect of UVAS was significantly greater than that of exogenously added adenine or guanine, which forms complementary base pairs with thymine. These data suggest that in addition to its filtering effect against UV radiation, UVAS also protects thymine by a direct molecule-to-molecule energy transfer process. The protective function of UVAS against UV irradiation is advantageous for this alga under strong UV irradiation.
Misonou
Taku
T
Department of Ecosocial System Engineering, Faculty of Engineering, Yamanashi University, Kofu, Yamanashi 400-8511, Japan, mist@ccn.yamanashi.ac.jp
Saitoh
Junko
J
Oshiba
Saori
S
Tokitomo
Yukiko
Y
Maegawa
Miyuki
M
Inoue
Yukio
Y
Hori
Hirokazu
H
Sakurai
Takeki
T
D000042:Absorption; D004249:DNA Damage / Q000187:drug effects; D019281:Dimerization; D010777:Photochemistry; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology* / Q000528:radiation effects; D010940:Plant Proteins / Q000302:isolation & purification / Q000494:pharmacology* / Q000528:radiation effects; D011687:Purines / Q000528:radiation effects; D011740:Pyrimidine Dimers / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D000461:Rhodophyta / Q000737:chemistry* / Q000378:metabolism; D014466:Ultraviolet Rays
D010936:Plant Extracts; D010940:Plant Proteins; D011687:Purines; D011740:Pyrimidine Dimers