FIG 1.
A highly conserved amino acid (Tyr-28) in SpoIIQ. (Top) Cartoon of the B. subtilis SpoIIQ (Q) protein, indicating its transmembrane domain (TMD) and the extracellular, SpoIIIAH (AH)-interacting domain. Q N-terminal residues 1 to 53 correspond to the QN truncation (middle) used in this study. (Bottom) A multiple-sequence alignment of the Q N terminus is shown for Q orthologs from various Bacillus and related species. Accession numbers for protein sequences are listed in Materials and Methods. Similar or identical residues are shaded light gray (60% identity), dark gray (80% identity), or black (100% identity). The conserved tyrosine (Tyr-28) residue is indicated.