Figure 3

N-terminal extended AAA-ATPase (AAA+) domain in DUF1703 family. Multiple sequence alignment for the N-terminal region of representative sequences from DUF1703 family and selected AAA+ structures together with the schematic diagram of the fold. Sequences are labeled according to gi number or PDB code and an abbreviation of the species name: Ac Azotobacter chroococcum, Bf Bacteroides fragilis, Bt Bacteroides thetaiotaomicron, Cc Chlorobium chlorochromatii, Ct Clostridium tetani, Fn Fusobacterium nucleatum, Mh Methanospirillum hungatei. Sequence gi numbers are colored according to taxonomy: with bacterial in black and archeal in red. The first and last residues numbers are indicated before and after each sequence with total sequence length following in square bracket. The numbers of excluded residues are specified in parentheses. Residue conservation is denoted in following scheme: uncharged, highlighted in yellow; charged or polar highlighted in grey; small, letters in red. Invariant active site residues are highlighted in red, while additional active site residues that have migrated in DUF1703 family sequences from typical Sensor I and Sensor II positions (highlighted in black) are highlighted in pink and blue. AAA+ motifs (Walker A, Walker B, Sensor I and Sensor II) are labeled above corresponding residue columns. Locations of predicted (gi:88603216) and observed (pdb:1fnn) secondary structure elements (E, β-strand; H, α-helix) are marked above the sequences and are colored according to the schematic representation shown in the bottom right corner. Core AAA+ helices and strands are colored blue and green, respectively, while inserted helices are colored orange. Walker A and B motif loops are labeled and colored red, with invariant DUF1703 family residues that correspond to AAA+ active site residues depicted as red circles. Typical Sensor I and Sensor II sites are labeled and colored gray, with positions of functional sites depicted as black circles. Migrated DUF1703 residues (indicated by broken black arrows) that could substitute for Sensor I and Sensor II are denoted by pink and blue circles, respectively.