Fig 1: Structural and biochemical analysis of the interactions between sNASPc and H3. (A) Schematics of domain architecture of H3. The schematics are drawn in proportion to the number of amino acids (length). Highlighted the sNASP binding sites. (B) ITC analysis of the sNASPc dimer titrated with the H3 N-terminal fragments. The buffer for ITC is 50 mM Tris pH 7.5, 200 mM NaCl. The thermodynamic parameters of the ITC assays are listed in the Supplementary Table S2. All raw data from the ITC assays are shown in the Supplementary Figure S3. (C) Wall-eyed stereoview of ribbon representation of the structure of the sNASPc dimer in complex with two H3 a3 fragments. The two protomers of sNASPc and sNASPc’ are colored in magenta and wheat, respectively, whereas the two molecules of H3 a3 are colored in blue. (D) Zoom in view on the a3-binding site of the sNASPc-H3 a3 dimer structure. Interacting residues of sNASPc (white) with H3 a3 (blue) are shown in sticks representation. Hydrogen bonds are indicated by dashed blacklines. The residues consisting of the hydrophobic pocket are labeled in red. (E-F) ITC analysis of the sNASPc dimer and its mutants (dimers) in the a3-binding groove, titrated with the H3 a3 peptide. The buffer for ITC is 50 mM Tris pH 7.5, 200 mM NaCl. The thermodynamic parameters of the ITC assays are listed in the Supplementary Table S3. All raw data from the ITC assays are shown in the Supplementary Figure S4. (G) ITC analysis of the sNASPc dimer and its mutants (dimers) in the a3-binding groove and the sNASPc dimer pre-bound with H3 a3, titrated with the H3 aN peptide. The buffer for ITC is 50 mM Tris pH 7.5, 200 mM NaCl. The thermodynamic parameters of the ITC assays are listed in the Supplementary Table S2. All raw data from the ITC assays are shown in the Supplementary Figure S3.