Nucleic acid binding by SAMHD1 contributes to the antiretroviral activity and is enhanced by the GpsN modification

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Yu, Corey H.
Bhattacharya, Akash
Persaud, Mirjana
Taylor, Alexander B.
Wang, Zhonghua
Bulnes-Ramos, Angel
Xu, Joella
Selyutina, Anastasia
Martinez-Lopez, Alicia
Cano, Kristin
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Nature Publishing Group
SAMHD1 impedes infection of myeloid cells and resting T lymphocytes by retroviruses, and the enzymatic activity of the protein—dephosphorylation of deoxynucleotide triphosphates (dNTPs)—implicates enzymatic dNTP depletion in innate antiviral immunity. Here we show that the allosteric binding sites of the enzyme are plastic and can accommodate oligonucleotides in place of the allosteric activators, GTP and dNTP. SAMHD1 displays a preference for oligonucleotides containing phosphorothioate bonds in the Rp configuration located 3’ to G nucleotides (GpsN), the modification pattern that occurs in a mechanism of antiviral defense in prokaryotes. In the presence of GTP and dNTPs, binding of GpsN-containing oligonucleotides promotes formation of a distinct tetramer with mixed occupancy of the allosteric sites. Mutations that impair formation of the mixed-occupancy complex abolish the antiretroviral activity of SAMHD1, but not its ability to deplete dNTPs. The findings link nucleic acid binding to the antiretroviral activity of SAMHD1, shed light on the immunomodulatory effects of synthetic phosphorothioated oligonucleotides and raise questions about the role of nucleic acid phosphorothioation in human innate immunity.
Open access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) applies
Medical research , Structural biology , Nucleic acid binding , SAMHD1 , Antiretroviral
Yu, C. H., Bhattacharya, A., Persaud, M., Taylor, A. B., Wang, Z., Bulnes-Ramos, A., Xu, J., Selyutina, A., Martinez-Lopez, A., Cano, K., Demeler, B., Kim, B., Hardies, S. C., Diaz-Griffero, F., & Ivanov, D. N. (2021). Nucleic acid binding by SAMHD1 contributes to the antiretroviral activity and is enhanced by the GpsN modification. Nature Communications, 12, Article: 731 (2021).