Fig. 3

Structure of SinR and the residues of E97, Y101, W104 and R105 (A), sequence alignment of the helical hook regions of SinR and SinI (B), Structural alignment of SinR (green) and SinI (pink) helical hooks (C). Residues are colored based on sequence similarity from Clustal Omega. Stars denote the residues involved in formation of the SinR tetramer interface. These residues in SinR were mutated to the corresponding residue of SinI to generate the SinR^quad mutant. Highly conserved amino acids are shown in grey shadow depending on similarity. C Left, conserved residues line the dimerization interface. Right, SinR residues necessary for tetramer formation are significantly different in SinI