Figure 3. Sequence homology in the RBDs of ELMO, c-Raf1, FHOD1 and Syx. Secondary structure prediction and sequence comparison between c-Raf1, FHOD1, ELMO-family proteins and Syx indicates an evolutionarily conserved Ras-Binding Domain (RBD) characterized by the presence of a ubiquitin-like subdomain. ELMO secondary structure was predicted with Jpred3. FHOD1 (Protein Data Bank ID code 3DAD) and Raf1 (Protein Data Bank ID code 1GUA) structures were used for the manual alignment with the ELMO RBDs. Conserved hydrophobic residues are highlighted in yellow, and conserved positively and negatively charged residues are indicated in blue and purple, respectively. Green residues depict the conserved Leucine residue in the ELMO proteins shown to be critical for RhoG and Arl4A GTPase binding. Charged residues in c-Raf involved in contacting Ras are shown in red. Residues highlighted in bold lettering indicate sequences that fold as helical. Asterisks indicate residues in Syx suggested to be involved in GTPase binding. E indicates β strand, H indicates α-helical.