Fig. 2: NMR analyses of SIB1 bound to WRKY33_C.

a Overlay of the 2D ¹H-¹⁵N HSQC spectra of ¹⁵N-labeled SIB1 in the free form (black) or in complex with unlabeled WRKY33_C (red). A few representative well-dispersed signals newly appeared in the complexed state are annotated with their assignments. b Chemical shift differences between free and complexed states of SIB1. The composite chemical shift changes (Δδ) were calculated using the empirical equation \(\varDelta \delta =\,\sqrt{{\varDelta \delta }_{H}^{2}+{({\varDelta \delta }_{N}/6)}^{2}}\), where Δδ_H and Δδ_N are the chemical shift changes in the ¹H and ¹⁵N dimensions, respectively. Residues unassigned only in the complexed state are indicated by gray bars. c The SSP scores of SIB1 in the free and complexed states calculated based on all available C^α, C^β, and H^N chemical shifts.