FIG. 2.

The sadARS locus. (A) The top of the panel shows the genomic organization of the sadARS region. The inverted triangle labeled Tn5 indicates the insertion site of the original sad-160::Tn5 mutant in the sadR-sadA intergenic region. The arrow within the Tn5 transposon indicates the direction of transcription of a putative promoter associated with the Tn5 insertion (see text for details). Each open reading frame is labeled with the annotation number (PA3946 to PA3948) from the P. aeruginosa genome project (www.Pseudomonas.com) and the corresponding sad gene designation. (B) Predicted structures of the SHK (SadS) and RRs (SadR and SadA). Abbreviations for the SHK are as follows: PBP, periplasmic binding protein domain; TM, transmembrane domain; PAS, PAS domain. The kinase, receiver (R), and HPT domains comprise the catalytic functions required for autophosphorylation and phosphotransfer activities. RR abbreviations: EAL, EAL family; R-Che, CheY-like phospho-receiver domain; HTH, HTH DNA binding domain.