Phylogenetic analyses of CzrA and NczA. Phylogenetic tree for the RND proteins was constructed using a neighbor-joining method. The tree was generated from multiple sequence alignment of protein sequences with higher than 55% identity to either C. crescentus CzrA or NczA, and the distances were calculated using CLUSTALX . The branches were color-coded as follows: blue, Alphaproteobacteria; red, Gammaproteobacteria; orange, Betaproteobacteria; green, Chlamidiales. Some of the most prevalent genera present in each branch of the tree are indicated. The two separate clusters corresponding to either C. crescentus orthologs are indicated as follows: A, NczA orthologous group; B, CzrA orthologous group.