Fig. 1

Comparison of the persistence of the wild-type TWIST1/E12 (TE) dimer and mutated R154P TE dimer with and without DNA. a Primary sequence alignment of the bHLH domains of the NEUROD1, TWIST1, and E2A proteins. Residues within the interhelical loops are underlined, h and m stand for human and murine, respectively. The arrows indicate the localization of the R154 residue and its equivalent on the other proteins. b-c 3D representation of the conserved TWIST1 (grey ribbon)/E12 (green ribbon) complex in the TE and TE R154P dimers in frontal (left) and lateral (right) views. The localization of the (b) arginine and the (c) proline 154 residues in the TWIST1/E12 and TWIST1/E12 R154P complexes on the TWIST1 ribbon is highlighted in CPK. d-e The root mean square fluctuation (RMSF) of TWIST1 and E12 amino acids were estimated during 10 ns in silico molecular dynamics (MD) simulations using the VMD 1.9.1 software. The graphical representation showed the calculated RMSF in angstroms (Å) for each (d) TWIST1 or (e) E12 residue in the mutated R154P TE model with (green line) or without (dashed green line) DNA anchor, and the TE model with (blue line) or without a DNA anchor (dashed blue line). f-g Box plots representing the root mean square deviation (1D-RMSD) by considering all of the atoms except hydrogen (NoH analysis) during 10 ns in silico molecular dynamics (MD) simulations. These distances were estimated during the MD simulations using the VMD 1.9.1 software (Graph of Labels Bonds). The NoH 1D-RMSD is shown in the (f) mutated R154P TE model with (green line) or without (gray line) DNA anchor, and (g) the TE model with (blue line) or without a DNA anchor (gray line)