1. Conserved motifs in the ABC
Conserved motifs in the ABC. Three characteristic motifs found in all ABC ATPases are represented by hatched red boxes.
Conserved motifs in the ABC. Three characteristic motifs found in all ABC ATPases are represented by hatched red boxes. The Walker A motif and the Walker B motif form the nucleotide-binding fold of the P-loop ATPase family. The signature motif, also called the C loop, is unique to ABC proteins and also interacts with ATP. Other characteristic motifs, including the Q loop and the H loop (also called the switch region), contain just one highly conserved residue and are represented by hatched green boxes. These residues make contacts with the γ-phosphate of ATP. In the context of the ABC dimer, the D loop makes contacts with Walker motif A of the other monomer. Sequences between the Q loop and the signature constitute a helical domain, also referred to as a structurally diverse region (SDR), that contains residues important for the interaction of ABC proteins with their membrane partners.
Amy L. Davidson et al. Microbiol. Mol. Biol. Rev. 2008; doi: /MMBR