Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.99.3 (PRE)
 1,923 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cyclobutane pyrimidine dimer (CPD) and (6-4) photoproduct, two major types of DNA damage caused by UV light, are repaired under illumination with near UV-visible light by CPD and (6-4) photolyases, respectively. To understand the mechanism of DNA repair, we examined the resonance Raman spectra of complexes between damaged DNA and the neutral semiquinoid and oxidized forms of (6-4) and CPD photolyases. The marker band for a neutral semiquinoid flavin and band I of the oxidized flavin, which are derived from the vibrations of the benzene ring of FAD, were shifted to lower frequencies upon binding of damaged DNA by CPD photolyase but not by (6-4) photolyase, indicating that CPD interacts with the benzene ring of FAD directly but that the (6-4) photoproduct does not. Bands II and VII of the oxidized flavin and the 1398/1391 cm(-1) bands of the neutral semiquinoid flavin, which may reflect the bending of U-shaped FAD, were altered upon substrate binding, suggesting that CPD and the (6-4) photoproduct interact with the adenine ring of FAD. When substrate was bound, there was an upshifted 1528 cm(-1) band of the neutral semiquinoid flavin in CPD photolyase, indicating a weakened hydrogen bond at N5-H of FAD, and band X seemed to be downshifted in (6-4) photolyase, indicating a weakened hydrogen bond at N3-H of FAD. These Raman spectra led us to conclude that the two photolyases have different electron transfer mechanisms as well as different hydrogen bonding environments, which account for the higher redox potential of CPD photolyase.
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PMID:Similarities and differences between cyclobutane pyrimidine dimer photolyase and (6-4) photolyase as revealed by resonance Raman spectroscopy: Electron transfer from the FAD cofactor to ultraviolet-damaged DNA. 1681 85

A pyrimidine-pyrimidone (6-4) photoproduct and a cyclobutane pyrimidine dimer (CPD) are major DNA lesions induced by ultraviolet irradiation, and (6-4) photolyase, an enzyme with flavin adenine dinucleotide (FAD) as a cofactor, repairs the former specifically by light illumination. We investigated resonance Raman spectra of (6-4) photolyase from Arabidopsis thaliana having neutral semiquinoid and oxidized forms of FAD, which were selectively intensity enhanced by excitations at 568.2 and 488.0 nm, respectively. DFT calculations were carried out for the first time on the neutral semiquinone. The marker band of a neutral semiquinone at 1606 cm(-1) in H(2)O, whose frequency is the lowest among various flavoenzymes, apparently splits into two comparable bands at 1594 and 1608 cm(-1) in D(2)O, and similarly, that at 1522 cm(-1) in H(2)O does into three bands at 1456, 1508, and 1536 cm(-1) in D(2)O. This D(2)O effect was recognized only after being oxidized once and photoreduced to form a semiquinone again, but not by simple H/D exchange of solvent. Some Raman bands of the oxidized form were observed at significantly low frequencies (1621, 1576 cm(-1)) and with band splittings (1508/1493, 1346/1320 cm(-1)). These Raman spectral characteristics indicate strong H-bonding interactions (at N5-H, N1), a fairly hydrophobic environment, and an electron-lacking feature in benzene ring of the FAD cofactor, which seems to specifically control the reactivity of (6-4) photolyase.
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PMID:Characteristic structure and environment in FAD cofactor of (6-4) photolyase along function revealed by resonance Raman spectroscopy. 1691 12