Quantum yields of adenine photodimerization in poly (deoxyadenylic acid) and DNA

Clingen, Peter H.; Jeremy, Ross; Davies, Helen

doi:10.1016/s1011-1344(96)07420-9

Cited by 24 publications

(26 citation statements)

References 23 publications

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“…As yet, no dimeric photoproducts derived from guanine have been detected in DNA although a number of cross-links identified in UV-irradiated 16 S ribosomal RNA are indicative of their formation (7). Adenine, however, is known to undergo photoaddition reactions with adjacent adenine or 5′-thymine bases in duplex DNA (8–12) but with quantum yields (12,13) that are approximately 100-fold lower than for pyrimidine dimerization. The individual photoproducts can be prepared by irradiating the dinucleoside monophosphates d(ApA) and d(TpA) in aqueous solution at 254 nm (9,10,14).…”

Section: Introductionmentioning

confidence: 99%

High-resolution crystal structure of the intramolecular d(TpA) thymine-adenine photoadduct and its mechanistic implications

Davies

Malone

Gan

et al. 2007

Nucleic Acids Research

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A high-resolution crystal structure is reported for d(TpA)*, the intramolecular thymine–adenine photoadduct that is produced by direct ultraviolet excitation of the dinucleoside monophosphate d(TpA). It confirms the presence of a central 1,3-diazacyclooctatriene ring linking the remnants of the T and A bases, as previously deduced from heteronuclear NMR measurements by Zhao et al. (The structure of d(TpA)*, the major photoproduct of thymidylyl-(3′-5′)-deoxyadenosine. Nucleic Acids Res., 1996, 24, 1554–1560). Within the crystal, the d(TpA)* molecules exist as zwitterions with a protonated amidine fragment of the eight-membered ring neutralizing the charge of the internucleotide phosphate monoanion. The absolute configuration at the original thymine C5 and C6 atoms is determined as 5S,6R. This is consistent with d(TpA)* arising by valence isomerization of a precursor cyclobutane photoproduct with cis–syn stereochemistry that is generated by [2 + 2] photoaddition of the thymine 5,6-double bond across the C6 and C5 positions of adenine. This mode of photoaddition should be favoured by the stacked conformation of adjacent T and A bases in B-form DNA. It is probable that the primary photoreaction is mechanistically analogous to pyrimidine dimerization despite having a much lower quantum yield.

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Section: Introductionmentioning

confidence: 99%

High-resolution crystal structure of the intramolecular d(TpA) thymine-adenine photoadduct and its mechanistic implications

Davies

Malone

Gan

et al. 2007

Nucleic Acids Research

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“…Although a large number of publications deal with pyrimidine dimerization, very few focus on adenine dimer formation. [1][2][3][4][5][6][7][8] Yet, the photodimerization quantum yield of adenine single strands is the order of 10 -3 , 6 comparable to that of (6-4)pyrimidine-pyrimidone adducts (64PPs) in thymine single strands, 9 which have received considerable attention. 10 Intriguingly, the photodimerization yields dramatically drop in DNA duplexes and in RNA strands.…”

mentioning

confidence: 99%

Excited State Pathways Leading to Formation of Adenine Dimers

Bányász

Martínez‐Fernández

Ketola

et al. 2016

J. Phys. Chem. Lett.

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“…In general, the purine bases of DNA are far more resistant to photochemical alteration than the pyrimidines (16). Although two species of dimeric adenine photoadducts (17) and a thymine-adenine photoadduct (18,19) are known to form in UV-irradiated DNA and to constitute alkali-labile sites (8), their yields are very low (20,21) and they cannot account for the observed cleavage at A,, owing to the sequence context. To assist further characterization of the underlying photolesion, attempts were made to reproduce it in a shorter oligonucleotide retaining the same photoreactive sequence element.…”

Section: Resultsmentioning

confidence: 99%

A Sequence‐specific Alkali‐labile Photolesion Mapping to Adenine in Single‐stranded DNA

Bowden¹,

Davies²

1997

Photochem & Photobiology

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Abstract— Following UV irradiation at 254 nm and treatment with hot piperidine, single‐stranded 49‐mer and 12‐mer oligodeoxyribonucleotides have been shown by gel‐sequencing experiments to contain a prominent alkali‐labile cleavage site that maps to adenine in the sequence element 5′‐TTGATC‐3′. This behavior is abolished by single base substitutions within the photoreactive tract and does not occur with duplex DNA. The distinctive properties of the photolesion are consistent with the formation of an abasic site through initial loss of a photomodified adenine base of unknown structure. The presence of an abasic site is supported by the observations that the alkaline cleavage fragments are terminally phosphorylated and that strand scission can also be effected by spermidine and the tripeptide Lys‐Trp‐Lys.

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Quantum yields of adenine photodimerization in poly (deoxyadenylic acid) and DNA

Cited by 24 publications

References 23 publications

High-resolution crystal structure of the intramolecular d(TpA) thymine-adenine photoadduct and its mechanistic implications

High-resolution crystal structure of the intramolecular d(TpA) thymine-adenine photoadduct and its mechanistic implications

Excited State Pathways Leading to Formation of Adenine Dimers

A Sequence‐specific Alkali‐labile Photolesion Mapping to Adenine in Single‐stranded DNA

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