Models of bMunc13-2 segment-C (aa 704–742) with CaM generated by ROSETTA. Segment-C was docked into CaM (PDB-Code: 2O60). The N-terminus of bMunc13-2 segment-C interacts with the central α-helix (Model A) or the C-terminal amino acids of CaM (Model B). (A) The N-terminal EF-hands of CaM are colored in light gray, the C-terminal EF-hands are colored in dark gray; aa 704–742 of bMunc13-2 are highlighted in rainbow colors starting with blue from the N-terminus; the amino acid sequence is given. (B) Superimposition of Model A and B (RMSD of 3.04 Å). Red: Model A, blue: Model B; bright colors: segment-C, dark colors: CaM. (C) Zoom into the slight flexibility of the N-terminus in segment-C; aa 704–718 are displayed for segment-C, aa 67–77 and aa 139–148 for CaM. Cα–Cα distances are shown for the cross-links connecting E707 of segment-C with the respective Met residues of CaM, which are replaced by photo-Met for cross-linking. Red: Model A, blue: Model B; bright colors: segment-C, dark colors: CaM.