O4 -Alkylated-2-Deoxyuridine Repair by O6 -Alkylguanine DNA Alkyltransferase is Augmented by a C5-Fluorine Modification.
Chembiochem
; 19(6): 575-582, 2018 03 16.
Article
em En
| MEDLINE
| ID: mdl-29243336
ABSTRACT
Oligonucleotides containing various adducts, including ethyl, benzyl, 4-hydroxybutyl and 7-hydroxyheptyl groups, at the O4 atom of 5-fluoro-O4 -alkyl-2'-deoxyuridine were prepared by solid-phase synthesis. UV thermal denaturation studies demonstrated that these modifications destabilised the duplex by approximately 10 °C, relative to the control containing 5-fluoro-2'-deoxyuridine. Circular dichroism spectroscopy revealed that these modified duplexes all adopted a B-form DNA structure. O6 -Alkylguanine DNA alkyltransferase (AGT) from humans (hAGT) was most efficient at repair of the 5-fluoro-O4 -benzyl-2'-deoxyuridine adduct, whereas the thymidine analogue was refractory to repair. The Escherichia coli AGT variant (OGT) was also efficient at removing O4 -ethyl and benzyl adducts of 5-fluoro-2-deoxyuridine. Computational assessment of N1-methyl analogues of the O4 -alkylated nucleobases revealed that the C5-fluorine modification had an influence on reducing the electron density of the O4 -Cα bond, relative to thymine (C5-methyl) and uracil (C5-hydrogen). These results reveal the positive influence of the C5-fluorine atom on the repair of larger O4 -alkyl adducts to expand knowledge of the range of substrates able to be repaired by AGT.
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MEDLINE
Assunto principal:
O(6)-Metilguanina-DNA Metiltransferase
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Desoxiuridina
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Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article