FIG 5.

Residues involved in the interaction with the ArmZ-like antirepressor are conserved in MexZ orthologs from various bacteria. Genes encoding clustered orthologs of MexZ/MexX/MexY or ArmZ/PA5470 were identified in bacterial genomes using MultiGeneBlast (44). Only 27 genomes containing two sets of MexZ/MexX/MexY and ArmZ/PA5470 orthologs were selected for the analysis (see Data Set S3 in the supplemental material). (A) Phylogenetic tree of the identified MexZ orthologs constructed using COBALT (67) by the use of the neighbor-joining method. C. serinivorans, Comamonas serinivorans; D. acidovorans, Delftia acidovorans; C. testosteroni, Comamonas testosteroni; R. solanacearum, Ralstonia solanacearum; N. elongata, Neisseria elongata; P. sneebia, Providencia sneebia; P. stuartii, Providencia stuartii; X. bovienii, Xenorhabdus bovienii; X. hominickii, Xenorhabdus hominickii; M. morganii, Morganella morganii; P. fontium, Pragia fontium; S. fonticola, Serratia fonticola; P. carotovorum, Pectobacterium carotovorum; K. cowanii, Kosakonia cowanii; S. flexneri, Shigella flexneri; S. dysenteriae, Shigella dysenteriae. (B) Sequence alignment of the N-terminal parts of MexZ orthologs (corresponding to amino acids 1 to 56 of P. aeruginosa MexZ). Sequences are ordered as in the tree, amino acids identical to those in P. aeruginosa MexZ are highlighted in gray, and residues corresponding to P. aeruginosa MexZ residues participating in the interaction with its antirepressor are indicated in red. The consensus sequence (amino acids occurring in more than 60% of proteins) and bars representing conservation are presented for MexZ orthologs identified in genomes with and without identified ArmZ/PA5470 orthologs. Full alignments are included in Fig. S3 and S4, respectively.