Figure 3
Conservation and structure homology of the K13 BTB fold. (a) Linear schematic representation of the BTB fold of some BTB-containing protein families. Yellow arrows and cyan cylinders represent strands and helices, respectively. Stars in magenta correspond to the 10% most conserved K13 BTB amino acid sites (based on the ranking of the λ substitution rates, FuncPatch analysis; Supplementary Dataset S1). Structural elements are labelled. (b) Maximum-likelihood unrooted phylogenetic tree of the BTB core fold using a few reference sequences per BTB-containing protein family. Each BTB-containing protein family forms a monophyletic group, identified with a colored background. K13 BTB is written in red color and clusters with the KCTD protein family of BTB-containing proteins. (c) Patch of slowly evolving amino acid sites in a three-dimensional view of PfK13 BTB. The amino acid sites are labelled using the PfK13 sequence as reference. (d) Superposition of the BTB fold of K13 with that of two members of the KCTD protein family. The most conserved amino acid sites for each protein was based on FuncPatch analysis and are shown in magenta, orange and red for K13, SHKBP1 and KCTD17, respectively. Other amino acid sites are shown in white, green, and cornflower blue for K13, SHKBP1 and KCTD17, respectively. Three common positions were identified in the BTB conserved patches of K13, SHKBP1 and KCTD17: 357 on the B2-B3 loop and 397–398 on the B4-A4 loop.
