Fig. 1.

Phylogenetic trees for the 5 families of proteins in the AI-2E superfamily (a–e) as well as for the complete superfamily (f). a–e Families 1-5, respectively. f The full superfamily tree showing the positioning of families 1-5 relative to each other. The dendogram corresponding to the tree in f is presented in figure S2. It is based on the multiple alignment shown in figure S1. Programs used to derive the trees have been described (CLUSTAL × [24] and TreeView [25]). Protein abbreviations for all members of the AI-2E superfamily can be found in table S1 (alphabetically arranged) and tables S3–S7 for the 5 families (1–5, respectively). The standard abbreviations used in our laboratory and many others include three letters often followed by a number. The first capitalized letter refers to the genus name while the second two small letters are the first two letters of the species name. Thus, Eco2 refers to the second paralogue in E. coli.