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SENSITIVITY OF DNA REPAIR‐DEFICIENT STRAINS OF ESCHERICHIA COLI K‐12 TO VARIOUS FUROCOUMARINS AND NEAR‐ULTRAVIOLET RADIATION
Author(s) -
Leonard I.,
Smith Kendric C.
Publication year - 1981
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1981.tb05424.x
Subject(s) - furocoumarins , escherichia coli , dna , dna damage , chemistry , dna repair , photochemistry , biophysics , biology , biochemistry , gene
— Survival curves were obtained for DNA repair‐deficient strains of Escherichia coli K‐12 ( polA1, uvrB5 , and recA56 ) exposed to near‐ultraviolet radiation [black light (BL)] in the presence of the DNA cross‐linking agent 8‐methoxypsoralen (8‐MOP) or in the presence of photosensitizers forming primarily monoadducts with DNA [angelicin; 3‐carbethoxypsoralen (3‐CPs); 5,7‐dimethoxycoumarin (DMC)], and after exposure to blue light (BluL) in the presence of 8‐MOP or 3‐CPs. An interpretation of these data suggests that DNA polymerase I is required for the major pathway of monoadduct repair, but appears to play little or no role in the repair of 8‐MOP cross‐links. The uvrB and recA strains were very sensitive, both to the cross‐linking agent and to the monoadduct formers. The markedly different results for BL plus DMC or 3‐CPs compared to angelicin suggests that the DMC and 3‐CPs monoadducts are repaired by a different mechanism than are the angelicin monoadducts, or else DMC and 3‐CPs undergo photochemical side reactions that produce DNA lesions other than the expected monoadducts. From photochemical evidence, we predicted that fewer 8‐MOP monoadducts should be converted to cross‐links by BluL vs BL; this appears to be the case. 3‐CPs showed dramatically different biological results when irradiated with BL vs BluL, suggesting that 3‐CPs may form more types of photoproducts than the expected monoadducts; BluL, however, appears to favor monoadduct formation.