a, b, Alignments of the nucleotide-binding (a) and transmembrane domains (b). The conserved tyrosines preceding the cytosolic gate helix of the NBD and the periplasmic gate are highlighted with a red arrow and red box in a and b, respectively. Transmembrane helices and cytosolic and periplasmic gate helices are shown as green and beige cylinders, respectively. Blue sequence labels indicate predicted teichoic acid transporters. All O-antigen transporter NBDs except for K. pneumoniae O2a contain predicted CBDs at their C termini, which are not shown. c, Alignment of the C-terminal region of AaWzt with the corresponding domains from the E. coli O9a (Protein Data Bank accession number 2R5O) and R. terrigena (Protein Data Bank accession number 5HNO) transporters. Sequences were aligned in CLUSTAL Omega and displayed in Jalview coloured by sequence identity.