Fig. 3: Allosteric site binders alter the conformation and dynamics of FUT8.

a The FUT8-CHX structure (this study) is superimposed on the FUT8 holo Structure (PDB code: 6TKV). CHX binding induces conformational changes in the ₂₄₇NWRYATG₂₅₃ loop. CHX, GDP, and key residues are shown as sticks. The main structures of the protein are represented as cartoons. b The FUT8-NH125 (this study, blue) and FUT8 holo (PDB code: 6TKV, green) structures are superimposed. The overall structures align closely, with no major conformational changes observed in the global fold upon NH125 binding. The allosteric inhibitor binding site (indicated by a red oval) is located distally from the extensive dimer interface (indicated by a dashed box), indicating that the inhibition mechanism is independent of quaternary structural perturbations. c The FUT8 apo, FUT8-CHX, FUT8-NH125, and FUT8 holo structures are superimposed, highlighting the flexibility of the ₂₁₅NKG₂₁₇ loop. The receptor glycan and K216 are shown as sticks. The main structures of the protein are represented as cartoons. d Comparative conformational distribution of the Apo (red scatter plot) and NH125-bound (blue scatter plot) states, projected onto the first two principal components (PC1 and PC2) from a combined analysis of all six molecular dynamics trajectories aligned to a common reference. Encircled clusters represent metastable conformational states. The relative free energy value (in kJ/mol) for each cluster is annotated, with the global minimum for each system designated as 0 kJ/mol. NH125 binding dramatically reorganizes the conformational ensemble, stabilizing a different global minimum state and altering the stability of functional basins, effectively trapping the enzyme in a non-productive conformation and illustrating the structural basis for its allosteric inhibitory mechanism. Source data are provided as a Source data file.