Photochemistry Nucleic acid

Molecular mechanisms in nucleic acid photochemistry I. Sensitized photochemical splitting of thymine dimer. J. Amer. chem. Soc. 88, 813 (1966). 

Blaney, R., Al-Nakib, T., Davies, R., and Jeremy, H., A fluorogenic actinometer for nucleic acid photochemistry utilizing 1-deazapurine 3-oxide, Photochem. Photobiol, 57, 380, 1993. 

Moucheron C, Kirsch-De Mesmaeker A, Kelly JM (1998) Photophysics and Photochemistry of Metal Polypyridyl and Related Complexes with Nucleic Acids. 92 163-216... 

Cadet J, Vigny P (1990) In Morrison H (ed) Bioorganic Photochemistry. Photochemistry and the Nucleic Acids. Wiley and Sons, New York, vol 1, p 1... 

The photochemistry of the polynucleotides has been elucidated primarily by studies of the photochemical behavior of the individual pyrimidine and purine bases (the ribose and phosphate groups would not be expected to undergo photochemical reactions in this wavelength range). These studies have shown the pyrimidines (cytosine and thymine) to be roughly ten times more sensitive to UV than the purines (adenine and guanine.) Thus we would expect most of the photochemistry of the nucleic acids to result from the action of light on the pyrimidines. 

Very important information concerning the photochemistry of the nucleic acids was furnished by the report of Beukers and Berends that irradiation of frozen solutions of thymine produces a stable photoproduct corresponding to dimerization of the thymine/58 This photoproduct has been subsequently identified as a cis-syn-cis dimer ... 

There is always interest in the photochemistry of the pyrimidine nucleic acid bases and related simple pyrimidinones, due to its importance in genetic mutation. In addition to damaging DNA, photo-induced reactions may also repair the damage, as in the reduction, by FADH, of the thymine glycol 64 back to thymine <06JACS10934>. Another report related to repair of DNA involved a model study, by means of the linked dimer 65, of the involvement of tryptophan in the electron-transfer leading to reversion of thymine oxetane adducts <06OBC291>. 

Cimino, C.P., Camper, H.B., Isaacs, S.T., and Hearst, J.E. (1985) Psoralens as photoactive probes of nucleic acid structure and function Organic chemistry, photochemistry, and biochemistry. Annu. Rev. Biochem. 54, 1151-1193. 

Orotic acid readily forms dimers even when irradiated in liquid medium [582, 583]. 5-Bromouracil (5-BrU) in DNA is dehalogenated, rather than forming cyclobutane-type dimers. Such DNA derivatives are more sensitive to ultraviolet irradiation than normal DNAs [584-594], Irradiation of 5-bromo-uracil and derivatives in aqueous medium produces 5,5 -diuracil [590, 591]. However, derivatives such as 3-sbutyl-5-bromo-6-methyluracil have been reported to yield cyclobutane dimers either by irradiation of frozen aqueous solutions, or by catalysis with free radical initiators, such as aluminium chloride, ferric chloride, peroxides or azonitriles [595]. 5-Hydroxymethyluracil is reported to dimerize very slowly in frozen water at 2537 A [596]. The fundamental research in the photochemistry of the nucleic acids, the monomeric bases, and their analogues has stimulated new experiments in certain micro-organisms and approaches in such diverse fields as template coding and genetic recombination [597-616]. 

A. D. McLaren and D. Shugar, Photochemistry of Proteins and Nucleic Acids, Pergamon, Oxford, 1964... 

Nucleic Acid Derivatives, Advances in the Photochemistry of (Burr).. . ... 

L. and Miranda, M.A. (2000) Tiaprofenic acid-photosensitized damage to nucleic acids a mechanistic study using complementary in vitro approaches. Photochemistry and Photobiology, 71, 499-505. 

Although a signal was detected also in irradiated pyrimidine solutions under similar conditions, it was attributed to dissociation products of the pyrimidine molecule and not to photoionization. If the purine solutions contained ethanol, then the signal of the CH3CHOH radical could also be detected this did not happen in ethanolic pyrimidine solutions. The possible importance of photoionization as the primary process in the photochemistry of nucleic acid derivatives has been supported by Kearns, from a study of photoionization in anthracene single crystals.115 He concluded that anthracene photoionization occurred via the interaction of two singlet excitons. 

The products resulting from this energy absorption in aerated water are H, OH, H02, H202, and e3q in concentrations which depend upon the dose rate and upon the pH of the solution, and the nature of the solute molecules.133 These species react with dissolved nucleic acid derivatives. There is a great difference between this sort of interaction and that in photochemistry where only the solute molecule absorbs the energy, and the ensuing reactions are those of the excited solute molecule. 

Shugar, D., Photochemistry of Nucleic Acids and Their Constituent8, State Institute Hyg. Warsaw (1961) Chem. Abstr., 55, 1722 (1961). 

Phosphorescence and photochemistry of aromatic amino acids have been reported.481-483 Triplet states of nucleic acids have also been detected. For example, the phosphorescence of DNA equals the sum of the slow emissions from deoxyadenosine and deoxyguanosine monophosphates present, indicating that only the purine bases phosphoresce.484... 

B-76MI21302 S. Y. Wang in Photochemistry and Photobiology of Nucleic Acids , Academic... 

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