Effect of ß,γ-CHF- and ß,γ-CHCl-dGTP halogen atom stereochemistry on the transition state of DNA polymerase ß.
Biochemistry
; 51(43): 8491-501, 2012 Oct 30.
Article
en En
| MEDLINE
| ID: mdl-23043620
ABSTRACT
Recently, we synthesized the first individual ß,γ-CHX-dGTP diastereomers [(R)- or (S)-CHX, where X is F or Cl] and determined their structures in ternary complexes with DNA polymerase ß (pol ß). We now report stereospecificity by pol ß on the mixed ß,γ-CHX diastereomer pairs using nuclear magnetic resonance and on the separate diastereomers using transient kinetics. For both the F and Cl diastereomers, the R isomer is favored over the S isomer for G·C correct incorporation, with stereospecificities [(k(pol)/K(d))(R)/(k(pol)/K(d))(S)] of 3.8 and 6.3, respectively, and also for G·T misincorporation, with stereospecificities of 11 and 7.8, respectively. Stereopreference for the (R)-CHF-dGTP diastereomer was abolished for k(pol) but not K(d) with mutant pol ß (R183A). These compounds constitute a new class of stereochemical probes for active site interactions involving halogen atoms. As Arg183 is unique in family X pols, the design of CXY deoxyribonucleotide analogues to enhance interaction is a possible strategy for inhibiting BER selectively in cancer cells.
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1
Bases de datos:
MEDLINE
Asunto principal:
ADN Polimerasa beta
/
Nucleótidos de Desoxiguanina
/
Halógenos
Límite:
Humans
Idioma:
En
Revista:
Biochemistry
Año:
2012
Tipo del documento:
Article
País de afiliación:
Estados Unidos