Fig. 5: Intermolecular interactions observed in apo and nikkomycin-treated R. delemar.

a Overlay of 2D ¹³C-¹³C correlation spectra with short 53-ms CORD mixing (orange) and 1-s PDSD mixing (cyan) on apo R. delemar sample. The dashed line box shows the spectral region where the zoomed-in view is shown in panel (d). b Spatial interactions between cell wall polysaccharides and proteins mapped onto carbon and nitrogen sites within biomolecules, including isoleucine (I), β−1,3-glucan (B), various chitosan (Cs) forms, and chitin (Ch) types. Intramolecular correlations are represented by gray boxes along the diagonal, while off-diagonal spots denote physical, intermolecular contacts observed solely in the apo sample (cyan), only in the nikkomycin-treated sample (orange), or in both samples (green). All molecular forms are depicted for interactions involving a carbon site with unspecified allomorph assignment. c NMR-derived structural representation of physical contacts between cell wall polysaccharides in either the apo (blue lines) or drug-treated (magenta lines) sample, excluding those common to both. Arrowheads indicate polarization transfer directionality. Dashed lines signify the involvement of a specific subform of each of the two molecules in contact, while bold lines represent the interaction between at least two allomorphs of each molecule. Key carbon sites involved are numbered. d 2D ¹³C-¹³C correlation spectra of apo R. delemar measured with short (53 ms CORD; orange) and long (1 s PDSD; cyan) mixing showing cross-peaks between protein amino acids and carbohydrates. e Schematic summary of protein-carbohydrate interactions via the sidechain of an isoleucine residue.