Effects of substitutions at the 4' and 2 positions on the bioactivity of 4'-ethynyl-2-fluoro-2'-deoxyadenosine

Karen A. Kirby, Eleftherios Michailidis, Tracy L. Fetterly, Musetta A. Steinbach, Kamalendra Singh, Bruno Marchand, Maxwell D. Leslie, Ariel N. Hagedorn, Eiichi N. Kodama, Victor E. Marquez, Stephen H. Hughes, Hiroaki Mitsuya, Michael A. Parniak, Stefan G. Sarafianos

研究成果: Article査読

19 被引用数 (Scopus)

抄録

Nucleos(t)ide reverse transcriptase inhibitors (NRTIs) form the backbone of most anti-HIV therapies. We have shown that 4'-ethynyl-2-fluoro-2'- deoxyadenosine (EFdA) is a highly effective NRTI; however, the reasons for the potent antiviral activity of EFdA are not well understood. Here, we use a combination of structural, computational, and biochemical approaches to examine how substitutions in the sugar or adenine rings affect the incorporation of dA-based NRTIs like EFdA into DNA by HIV RT and their susceptibility to deamination by adenosine deaminase (ADA). Nuclear magnetic resonance (NMR) spectroscopy studies of 4'-substituted NRTIs show that ethynyl or cyano groups stabilize the sugar ring in the C-2'-exo/C-3'-endo (north) conformation. Steady-state kinetic analysis of the incorporation of 4'-substituted NRTIs by RT reveals a correlation between the north conformation of the NRTI sugar ring and efficiency of incorporation into the nascent DNA strand. Structural analysis and the kinetics of deamination by ADA demonstrate that 4'-ethynyl and cyano substitutions decrease the susceptibility of adenosinebased compounds to ADA through steric interactions at the active site. However, the major determinant for decreased susceptibility to ADA is the 2-halo substitution, which alters the pKa of N1 on the adenine base. These results provide insight into how NRTI structural attributes affect their antiviral activities through their interactions with the RT and ADA active sites.

本文言語English
ページ(範囲)6254-6264
ページ数11
ジャーナルAntimicrobial agents and chemotherapy
57
12
DOI
出版ステータスPublished - 2013 12

ASJC Scopus subject areas

  • 薬理学
  • 薬理学(医学)
  • 感染症

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