Molecular Competition for NKG2D Christopher A O'Callaghan, Adelheid Cerwenka, Benjamin E Willcox, Lewis L Lanier, Pamela J Bjorkman  Immunity  Volume 15, Issue 2, Pages 201-211 (August 2001) DOI: 10.1016/S1074-7613(01)00187-X

Figure 1 Biosensor Analyses of NKG2D Interacting with RAE1γ or H60 (A) Sensorgrams from typical equilibrium-based binding experiments. NKG2D was injected over surfaces coupled with RAE1γ (1941RU) or H60 (612RU). Sensorgrams predicted from a simple Langmuir 1:1 binding model (black lines) are overlaid with the specific response derived after subtraction of the background response from a control surface (dotted colored lines). (B) Plots of the equilibrium binding response (Req) from the sensorgrams as a function of NKG2D concentration. Best-fit binding curves to the experimental data are shown as thin red lines. Insets show Scatchard plots of the binding data. (C) Sensorgrams from typical kinetics-based binding experiments. NKG2D was injected over surfaces coupled with RAE1γ (30RU) or H60 (47RU). Global fitting of data to the 1:1 binding model is shown as thin blue lines Immunity 2001 15, 201-211DOI: (10.1016/S1074-7613(01)00187-X)

Figure 2 Binding of Tetrameric Unglycosylated Proteins to Proteins on Living Cells (A) Flow cytometric analyses of NKG2D-transfected (blue) and untransfected (green) Ba/F3 cells stained with phycoerythrin-labeled unglycosylated RAE1γ or H60 tetramers. (B) Flow cytometric analyses of RAE1γ or H60-transfected (blue) and untransfected (green) Ba/F3 cells stained with phycoerythrin-labeled unglycosylated NKG2D tetramers Immunity 2001 15, 201-211DOI: (10.1016/S1074-7613(01)00187-X)

Figure 3 Competition between RAE1γ and H60 for NKG2D Occupancy Aliquots of NKG2D were preequilibrated with the indicated proteins and equilibrated mixes were injected over biosensor surfaces coupled with RAE1γ or H60. Specific binding to each experimental surface is shown Immunity 2001 15, 201-211DOI: (10.1016/S1074-7613(01)00187-X)

Figure 4 Thermodynamic and Electrostatic Analyses of NKG2D-RAE1 and NKG2D-H60 Binding (A) van't Hoff analysis of affinity as a function of temperature. The natural log (ln) of KD values from equilibrium-based affinity measurements is plotted against inverse temperature (range: 10°C–37°C for RAE1γ and 20°C–37°C for H60). ΔH is derived from the slope of the best-fit line to the data points (slope = ΔH/R). As ΔH can change with temperature, van't Hoff plots are not strictly linear and the ΔH values obtained apply with highest precision at the midpoint of the range of temperatures used for the fit. (B) The log of KD values obtained from equilibrium-based affinity measurements is plotted versus the log of the sodium chloride concentration (1 mM to 1 M). The slope of the best-fit line to the data points (SKobs) is a measure of the contribution of electrostatic attraction to the binding affinity. (C) Arrhenius plots of the natural logarithm of the on and off rates for the NKG2D interactions derived over a range of temperatures (20°C–37°C). Solid lines show linear fits to the experimental data. The variation of the association and dissociation constants with temperature determines the slope of the curve from which the enthalpies of association (ΔH‡ass) and dissociation (ΔH‡diss) can be determined, respectively (slope = −Ea/R, ΔH‡ = −Ea − RT) Immunity 2001 15, 201-211DOI: (10.1016/S1074-7613(01)00187-X)

Figure 5 Free Energy Profiles of the NKG2D-RAE1γ and NKG2D-H60 Binding Reactions Reaction profiles illustrating the free energy changes occurring as NKG2D binds its ligands. The overall free energy changes of binding are represented by the lower left arrows between the unbound and the bound state Immunity 2001 15, 201-211DOI: (10.1016/S1074-7613(01)00187-X)