Fig. 5.

Conservation and gene structure. a Conservation within 828 profilin sequences. P. falciparum profilin residue numbers are marked on the X axis. Residue entropy (S) on the Y axis (black dots) was only calculated at sites present in >95 % of the sequences. S = 0 means 100 % conservation; higher S means more variation. The dots are connected with a thin black line to guide the eye. The orange horizontal line shows the mean residue entropy (0.40 for the N-terminal and 0.43 for the C-terminal fragment). The secondary structure elements of P. falciparum profilin are depicted as orange and black bars below the residue numbers. b Gene structure of Plasmodium profilin (PfPfn) and human profilin 4 (HsPfn4) in relation to the protein structure. Exons 1–4 of the Plasmodium profilin gene are shown as bars with different colors, and their lengths are in relation to the protein sequence in panel a. The protein segments encoded by the exons are colored accordingly in the 3D structure presentation of the Plasmodium protein. In the human profilin 4 gene, exon 1 corresponds to exons 1 and 2 in the Plasmodium profilin gene and encodes the entire N-terminal segment (black), while the C-terminal fragment (light gray) is encoded by 3, instead of 2, exons