Figure 2. Phylogeny and sequence conservation of the TatA family.
(A) Phylogenetic tree of TatA family members based on a sequence comparison to the end of the APH. The phylogenetic origins of the sequences are given around the edge of the tree: `Alpha’, `Beta’, `Gamma’, `Delta’, and `Epsilon’ refer to the five classes of the phylum Proteobacteria; `Bacilli’ and `Clostridia’ are classes within the phylum Firmicutes; `Actino’ refers to the phylum Actinobacteria; `Acido’ refers to the phylum Acidobacteria; `Cyano’ refers to the phylum Cyanobacteria; `Plants’ refers to plant chloroplast proteins. Asterisks mark the sequences of E. coli TatA/TatE (blue), E. coli TatB (orange), and the pea thylakoid TatA and TatB proteins Tha4 and Hcf106 (red). (B) Sequence logos for the three Tat subsets identified in (A). The logos correspond to the sequence region analyzed in (A) and use the sequence numbering of E. coli TatA and TatB. The secondary structure elements of the Tat proteins are shown under the logos and the position of the TMH polar residue is indicated with a red dot. The figure was generated using WebLogo 3.4 (Crooks et al., 2004).