Figure 5. ASCS experiments to identify intermolecular proximal residue pairs.

(a–c) Phe-, Ile- and Leu-selective CS experiments. The difference in the intensity reduction ratios (ΔRR) in the presence of Phe, Ile or Leu selectively ¹H-labeled in a ²H-background and uniformly ²H-labeled VSD were plotted against the residue numbers of VSTx1, respectively (left). The residues indicated by asterisks are those with the signal-to-noise ratios less than 10. The error bars were calculated based on the signal-to-noise ratios. Bars corresponding to the residues with significant intensity reductions (minimum values of ΔRR > 0.1) are colored. The backbone amide hydrogen atoms of the affected residues are shown as balls in the VSTx1 structure (PDB code 1S6X) and the candidates of the CS-source residues are shown as sticks in the VSD structure (PDB code 2KYH) (right). (d) Proximal residue pairs connected by dotted lines.