FIG 2.

SpoIID is conserved among Chlamydiae and is predicted to localize to the periplasm. (A) Alignment of SpoIID homologues of W. chondrophila, C. trachomatis, and C. pneumoniae. SP, signal peptide; SpoIID, predicted SpoIID domain. Red stars indicate conserved glutamic acid/aspartic acid residues. Colored amino acids indicate conserved properties using the following Clustal X color scheme: blue, hydrophobic; red, positively charged; magenta, negatively charged; green, polar; pink, cysteines; orange, glycines; yellow, prolines; cyan, aromatic. (B) Working model showing the potential periplasmic localization of chlamydial SpoIID and its suggested interactions with PG and RodZ. The interactions with RodZ might be indirect and might occur through the activity of an undetermined divisome component (gray protein with a question mark). The scissor indicates a potential cleavage of the signal sequence located in the inner membrane.