Fig. 4. The acidic IDR peptide (¹⁵N Ac-pep_rec) dynamically interacts with CXCL12.

Superposition of (a) ¹H-¹⁵N HSQC spectra of ¹⁵N Ac-pep_rec (0.1 mM) without (black) and with (orange) CXCL12 (1:1), (b) ¹H-¹⁵C HSQC spectra of ¹⁵N/¹³C Ac-pep_rec (0.1 mM) without (black) and with (orange) CXCL12 (1:1). Bar graphs showing (c) chemical shift perturbation (CSPs) and (d) peak intensity ratios (I/I₀) of ¹⁵N Ac-pep_rec (0.1 mM) upon addition of CXCL12 (1:1). e Peak intensity ratios of heteronuclear NOE with and without proton saturation (I_sat/I_ref), error bars were calculated by error propagation from the standard deviation (SD) of the average value of the noise in the saturated $⟨I_{noise,sat}⟩$ and non saturated reference $⟨I_{noise,ref}⟩$ spectra. f Ratios of R₂ and R₁ relaxation rates of ¹⁵N Ac-pep_rec (0.1 mM) without (black) and with CXCL12 (1:1) (orange). Data of one representative experiment performed on n = 2 biologically independent samples are presented as mean values +/− SD. Error bars are derived from relaxation data as described in methods. Amide resonances were not sequence specifically assigned and peaks were attributed arbitrary numbers. Source data are provided as a Source Data file.