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Nucleotide Sugar Pucker Preference Mitigates Excision by HIV‑1 RT

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journal contribution
posted on 18.09.2015, 00:00 by Ken Yamada, Alexander S. Wahba, Jean A. Bernatchez, Tatiana Ilina, Saúl Martínez-Montero, Maryam Habibian, Glen F. Deleavey, Matthias Götte, Michael A. Parniak, Masad J. Damha
A series of DNA primers containing nucleotides with various sugar pucker conformations at the 3′-terminus were chemically synthesized by solid-phase synthesis. The ability of wild-type (WT) HIV-1 reverse transcriptase (RT) and AZT-resistant (AZTr) RT to excise the 3′-terminal nucleotide was assessed. Nucleosides with a preference for the North conformation were more refractory to excision by both WT-RT and AZTr-RT. We found that DNA primers that contain North puckered-nucleotides at the 3′-terminus can also affect the translocation status of the RT/template/primer complex, which provides an underlying mechanism to avoid being excised. Together, these results point to a correlation between the sugar conformation of the 3′-terminal nucleotide, the precise position of HIV-1 RT on its nucleic acid substrate, and, in turn, its catalytic function. Nucleotide sugar conformation is therefore an important parameter in defining the susceptibility to RT-catalyzed phosphorolytic excision.