Light-induced cross-linking of DNA in the presence of a furocoumarin (psoralen)

Cole, Ronald S.

doi:10.1016/0005-2787(70)90119-x

Cited by 314 publications

(103 citation statements)

References 17 publications

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“…Linear dependence of cross-linking on light fluence has been reported for low-intensity continuous irradiation of 4,5',8-trimethylpsoralen with phage h DNA in vitro (Cole, 1970 hamster DNA in vivo (Ben-Hur & Elkind, 1973). While the kinetics of the in vivo reactions could be distorted if the DNA after isolation were of heterogeneous molecular weight (as mentioned above), this would not be the case for X DNA if shear breakage were avoided.…”

Section: Discussionmentioning

confidence: 95%

Low-level psoralen-deoxyribonucleic acid crosslinks induced by single laser pulses

Johnston¹,

Hearst²

1981

Biochemistry

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While many intercalated psoralens require a 1.3-ps relaxation time between absorption of the first and second photons for cross-link formation to occur, some psoralens can form cross-links within the lifetime of a 10-ns laser pulse. This effect is largely or completely oxygen independent. Structural, kinetic, and energetic considerations suggest that the 1.3-ps delay may be due to a conformational change in the deoxyribonucleic acid (DNA) at the intercalation site which could be required for proper alignment of the double bonds which react in the second photoreaction. The cross-links which can form with single pulses of light may result from intercalation complexes which are already in a conformation such that, E o r a l e n s are skin-photosensitizing compounds (furocoumarins), which intercalate between the base pairs of double-helical nucleic acids and, upon absorption of long-wave UV light, can form cyclobutane adducts to adjacent pyrimidines. Capable of photoreacting at both ends of the molecule, a favorably positioned psoralen can cross-link the double helix by reacting with pyrimidines on opposite strands lying above and below the intercalation site.In earlier work (Johnston et al., 1977), we utilized single pulses from a ruby laser (A = 347 nm) to produce monoadducts between 4'-(aminomethyl)-4,5',8-trimethylpsoralen (AMT)' and bacteriophage T4 DNA, with no cross-links detectable.Our interpretation of this result postulated the existence of an intermediate excited state which "decays" into a monoadduct capable of further photoreaction @e., forming a cross-link) only after a time interval long compared to the 15-1s duration of the laser pulse. We have measured the l / e time required for formation of a "cross-linkable" monoadduct to be 1.3 hs (Johnston et al., 1980) and suggested that a conformational change is required after formation of a monoadduct before it is capable of forming a cross-link. In the course of this measurement, which required the use of different laser sources, higher pulse energy, and an increased accuracy in cross-link detection over the original work, it was found that some cross-links are formed by two pulses of light spaced closer than 100 ns and indeed by single 15-11s pulses. Spacing two pulses farther apart than 1 ps simply increases the yield of cross-links, dramatically at the ruby wavelength and less dramatically at the wavelength of the Nd-YAG laser (355 nm) used in the two-pulse experiments. In the present work we have analyzed this effect and suggest that a certain subpopulation of intercalated psoralens is capable of forming a within 20 ns after absorption of an initial photon, a monoadduct is formed which can absorb a second photon and thence result in a cross-link. These intercalation sites may be distinguished by the type and sequence of base pairs at the site or, alternatively, at the moment of the pulse, random motions of the DNA may have brought those sites into a conformation which allows cross-linking without the 1.3-ps delay. Unlike "ordinary" cross-link...

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Section: Discussionmentioning

confidence: 95%

Low-level psoralen-deoxyribonucleic acid crosslinks induced by single laser pulses

Johnston¹,

Hearst²

1981

Biochemistry

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“…[22][23][24] These compounds intercalate into DNA double helices and in the presence of UV-A light peaking near 365 nm, form covalent cross-links between parallel DNA strands, thereby preventing replication of genetic material of the microorganism. [25][26][27] Likely acting as antifungals or insecticides, 28 psoralens are found in a variety of plants, including many citrus fruits, parsley, figs, and parsnips. 29 Psoralens are found in particularly high concentrations in peel of limes, a fruit that is cultivated in many regions where SODIS may be practically implemented.…”

Section: Introductionmentioning

confidence: 99%

Using Limes and Synthetic Psoralens to Enhance Solar Disinfection of Water (SODIS): A Laboratory Evaluation with Norovirus, Escherichia coli, and MS2

Harding¹,

Schwab²

2012

The American Society of Tropical Medicine and Hygiene

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We investigated the use of psoralens and limes to enhance solar disinfection of water (SODIS) using an UV lamp and natural sunlight experiments. SODIS conditions were replicated using sunlight, 2 L polyethylene terephthalate (PET) bottles, and tap water with Escherichia coli, MS2 bacteriophage, and murine norovirus (MNV). Psoralens and lime acidity both interact synergistically with UV radiation to accelerate inactivation of microbes. Escherichia coli was ablated > 6.1 logs by SODIS + Lime Slurry and 5.6 logs by SODIS + Lime Juice in 30-minute solar exposures, compared with a 1.5 log reduction with SODIS alone (N = 3; P < 0.001). MS2 was inactivated > 3.9 logs by SODIS + Lime Slurry, 1.9 logs by SODIS + Lime Juice, and 1.4 logs by SODIS in 2.5-hour solar exposures (N = 3; P < 0.05). MNV was resistant to SODIS, with < 2 log reductions after 6 hours. Efficacy of SODIS against human norovirus should be investigated further.

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“…A C4-cycloaddition to the 5,6-double bond of pyrimidine bases occurs: furocoumarins can photoreact either with their 3,4-or 4',5'-double bond, forming therefore two types of photoadducts. Moreover, behaving as bifunctional agents, they can form adducts, in which one furocoumarin molecule is linked with two pyrimidine bases; in this case an inter-stand crosslinking is formed in native DNA [9][10][11]. It has been shown by Cole [10] and Chandra et al [12][13][14] that the formation of inter-strand crosslinking is responsible for the photodynamic damage to biological systems by psoralen.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, behaving as bifunctional agents, they can form adducts, in which one furocoumarin molecule is linked with two pyrimidine bases; in this case an inter-stand crosslinking is formed in native DNA [9][10][11]. It has been shown by Cole [10] and Chandra et al [12][13][14] that the formation of inter-strand crosslinking is responsible for the photodynamic damage to biological systems by psoralen. The intercalation of a furocoumarin molecule between the planes of two base pairs of native DNA is strongly affected by substitutions in the furocoumarin molecule.…”

Section: Introductionmentioning

confidence: 99%

Structure specificity of polydeoxyribonucleotides for the photoreaction with psoralen

et al. 1973

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Light-induced cross-linking of DNA in the presence of a furocoumarin (psoralen)

Cited by 314 publications

References 17 publications

Low-level psoralen-deoxyribonucleic acid crosslinks induced by single laser pulses

Low-level psoralen-deoxyribonucleic acid crosslinks induced by single laser pulses

Using Limes and Synthetic Psoralens to Enhance Solar Disinfection of Water (SODIS): A Laboratory Evaluation with Norovirus, Escherichia coli, and MS2

Structure specificity of polydeoxyribonucleotides for the photoreaction with psoralen

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