Fig. 5: Protein strain analysis reveals local deformations associated with phosphorylation.

a Schematic showing mechanical strain from pairwise comparisons of phosphorylated vs. non-phosphorylated structures, focusing on overlap with phosphosites, functional sites, and background (i.e., any other residues). b Boxplot comparing strain across different protein regions for real data vs. bootstrap samples (randomized strain distributions). c Overlap between highly strained phosphosites and highly strained functional sites. Proteins with clear co-straining in both sites are listed, with red-highlighted UniProt IDs indicating literature-supported functional roles for phosphorylation. Asterisks mark phosphosites within functional sites. d Histogram of distance between co-strained phosphosite and functional site. e, f Predicted mechanical coupling between phosphosite T220 and ATP binding site in human casein kinase I, isoform delta, with extensive stretch per residue averaged over multiple pairwise comparisons, with the standard deviation represented in the shaded bands. The comparison shown in the structure is 7P7F_B vs 4HNF_A. g, h Example of no mechanical coupling in discoidin-2 from Dictyostelium discoideum, which binds calcium ions and carbohydrates in distinct domains, showing no strain increase either at the phosphosite (H84) or at ligand-binding sites. The comparison shown in the structure is 2VME_B vs 2VMC_A. Strain from phosphorylated vs. non-phosphorylated structures is color-coded by stretch magnitude (1.0–1.2); phosphosites in magenta, ligands in white. Shaded bands indicate standard deviation. i Schematic representation of strain mapping in a structural comparison, highlighting the high-strain manifold. The reference structure (in white) is contrasted with the deformed structure (coloured according to the strain magnitude). j Representation of phosphosite vicinity and functional site in the high-strain manifold across groups. Statistical significance was determined using two-tailed Mann–Whitney U tests. In box-plots throughout the figure, the median is represented by the line inside the box. The box represents the interquartile range (IQR), while whiskers extend to the minimum and maximum values within 1.5 IQR. Points beyond the whiskers are outliers. Source data are provided as a Source Data file.