Figure 3 | Scientific Reports

Figure 3

From: Effects of T592 phosphomimetic mutations on tetramer stability and dNTPase activity of SAMHD1 can not explain the retroviral restriction defect

Figure 3

NMR-based dNTPase assay.

(A) NMR signals of the H6 proton of the thymine base (shown in bold) display distinct chemical shift in thymidine triphosphate (dTTP) and unphosphorylated thymidine nucleoside (dT). NMR spectra are acquired at regular time intervals following addition of SAMHD1. (B) Reaction progress curves are obtained by plotting NMR signal intensities as a function of time. Progress curves obtained at different GPT concentrations are shown. Steady-state rates are determined by linear fitting. (C) The plot of the reaction rate versus GTP concentration reveals dependence of the enzymatic activity on the binding of GTP to the A1 allosteric site. The curve shows the fit of the data to a simple EC50 equation y = ymax *x/(EC50+x).

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