Effect of 尾,纬-CHF- and 尾,纬-CHCl-dGTP Halogen Atom Stereochemistry on the Transition State of DNA Polymerase 尾

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• 作者：Keriann Oertell ; Yue Wu ; Valeria M. Zakharova ; Boris A. Kashemirov ; David D. Shock ; William A. Beard ; Samuel H. Wilson ; Charles E. McKenna ; Myron F. Goodman
• 刊名：Biochemistry
• 出版年：2012
• 出版时间：October 30, 2012
• 年：2012
• 卷：51
• 期：43
• 页码：8491-8501
• 全文大小：578K
• 年卷期：v.51,no.43(October 30, 2012)
• ISSN：1520-4995

文摘

Recently, we synthesized the first individual 尾,纬-CHX-dGTP diastereomers [(R)- or (S)-CHX, where X is F or Cl] and determined their structures in ternary complexes with DNA polymerase 尾 (pol 尾). We now report stereospecificity by pol 尾 on the mixed 尾,纬-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路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路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 尾 (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.