Fig. 4. Different CHIKV HVD/SH3 complexes demonstrate specific CSP signatures.

Superposition of the expanded ¹H-¹⁵N best-TROSY spectra of the apo ¹⁵N-CHIKV HVD (black cross peaks) with the corresponding spectra of ¹⁵N-CHIKV HVD, titrated with unlabelled SH3 domains. The SH3-A-, SH3-B-, SH3-C- and SH3-All-specific cross peaks are indicated in red, blue, green and pink, respectively. (A) The N-terminal element of Site 1, represented by aa 70–74; (B) The N- and C-terminal elements of Site 2, represented by aa 101–105 and 108–111, respectively; and (C) Site 3, represented by aa 164–172. Arrows indicate the directions of the chemical shift perturbations in the presence of the SH3 domains at increasing concentrations. Several cross peaks of these sequences are not shown because they are either located in a crowed area of the spectrum or the intensity decreased below the detection limit.