Fig. 4: Ligand-induced modulation of LBD conformational dynamics.
a, Woods plots from HDX-MS experiments. Each horizontal bar corresponds to a peptide representing a fragment of the mGluR2 LBD sequence identified by mass spectrometry. The y position of each bar corresponds to the peptide’s change in % deuteration in the presence versus in the absence of 10 mM glutamate, such that negative values correspond to increased protection in 10 mM glutamate and positive values correspond to decreased protection in 10 mM glutamate (top). Bottom: change in deuteration in the presence versus absence of 10 µM BINA, added on top of 10 mM glutamate. Gray bars represent peptides showing ≤10% change in deuteration between the compared conditions. Colors represent the different exchange time points. Vertical, dashed red lines indicate ligand-contacting residues in the 4XAQ crystal structure. b, Scatter plot comparing deuteration differences for 10 mM Glu versus 0 mM Glu, for the same peptides monitored either in the LBD-alone construct or in the full-length mGluR2 construct at t = 13,200 s. c, Uptake plots highlighting changes in protection in regions of interest in the mGluR LBD—peptides 55–62 and 290–300 show distinct uptake patterns for glutamate-bound versus glutamate-free conditions. Peptides 147–157 differ between LBD-alone and full-length constructs in the absence of glutamate (compare gray versus pink). Peptides 216–226 demonstrate glutamate-dependent and BINA-dependent differences (compare pink versus turquoise versus blue). Dots correspond to average deuterium uptake for each peptide across three independent (n = 3) HDX-MS replicates.
