Nucleotide binding to Lpg2603 depends on IP6 binding.
A, representative isothermal titration calorimetry data for Lpg2603 binding to AMP-PNP in the absence of IP6. For all instances, Lpg2603 is at 100 μm in the cell, and AMP-PNP is present at 2 mm in the titration syringe to a final molar ratio of 1:4. B, representative isothermal titration calorimetry data for Lpg2603 binding to AMP-PNP in the presence of IP6. Best fit parameters were as follows: n = 1.54; ΔH = −5.79 kCal/mol. C, representative isothermal titration calorimetry data for Lpg2603 K111A binding to AMP-PNP. D, representative isothermal titration calorimetry data for Lpg2603 K111A binding to AMP-PNP in the presence of IP6. The results are representative of two independent experiments.