Figure 2. Residues of interest as sequence alignments, 3D structures, and genomic locations.

Sequence alignments of a) ArlI, b) ArlJ and e) CirA from Hfx. volcanii with homologs from four additional haloarchaeal species and five non-halophilic archaeal species of different phyla. Regions of the alignment surrounding the mutated residues from Table 1 are shown; other regions of the protein are either omitted or set to 25% transparency to ease visualization. Conserved residues across species are indicated in shades of blue, with darker blues corresponding to highly conserved residues. The ArlI conserved Aspartate Box motif and the CirA Walker A domain are indicated. c) Residues of ArlI and ArlJ corresponding to ΔpilA[1–6] suppressor mutations mapped to the AlphaFold structure predictions of the ArlI hexamer and ArlJ dimer, respectively. Yellow circles indicate the residues of interest. d) cirA is found between the archaellin genes (arlA1, arlA2) and the rest of the arl genes (arlC/E–arlJ). It is transcribed in the opposite direction as the arl genes. The genic locations of the residues corresponding to the mutations found in the ΔpilA[1–6] suppressor mutants as well as hypermotile mutants from a previous study²⁵ are indicated, along with the conserved Walker A and Walker B motifs.