Figure 3. Evolutionary Conservation of Residues Involved in Munc13–1 Homodimerization and Munc13–1/α-RIM Heterodimerization.

(A) and ( B) Sequence alignments of the Munc13/Unc13 N-terminal sequences including the C ₂A domain and the C-terminal α-helical extension (C-ter) (A), and of the α-RIM/Unc10 ZF domains (B). The eight cysteine residues conserved in all α-RIM/Unc10 ZF domains are shown in white on a black background. Residues conserved in more than 70% of the sequences are highlighted in white with a red background. Residues involved in homo and heterodimerization are indicated by an asterisk (*) above the sequences. The secondary structure elements are indicated below the alignments. Species abbreviations: Am, Apis mellifera; Ce, Caenorhabditis elegans; Dm, Drosophila melanogaster; Dn, Danio rerio; Rn, Rattus norvegicus; Tn, Tetraodon nigroviridis; Xt, Xenopus tropicalis.