Figure 3

Phylogenetic tree and alignment of CHASE domains. (A) Phylogenetic tree of CHASE domains from five different subgroups (see Additional file 1 for all subgroups). Sequences of CHASE domains used for tree building are labelled with gi numbers and the start and end position of the respective CHASE domain. (B) Section of CHASE family alignment containing sequences used for the evolutionary rate analysis of the individual amino acids. The evolutionary site rate categories for each subgroup are given below the alignment, ranging from 1 (slow rate of evolution) to 8 (fast rate of evolution). Amino acid positions selected for experimental analysis (W244, K297, F304, R305, T317) are highlighted in orange, positions that are conserved throughout all CHASE sequences in grey. Interruptions of the alignment are indicated by two dots, gaps in the alignment by dashes. (See Additional file 1 for full sequence alignment). The selected blocks relate to the CRE1/AHK4 sequence 238–249, 292–308 and 313–321, respectively.