Figure 4
Identification of three main types of ST proteins according the X 4 pattern. (A) Percentages of the different types of ST proteins and the most typical X4 pattern found in each type. (B, C) Comparisons between type I and type IIa ST proteins represented using Two Sample Logo. (B) Comparison of 25 amino acids repeats of type I versus type IIa. The main difference is found in the X4 sequence. (C) Comparison of 26 amino acids repeats of type I versus type IIa. The difference in the conserved X4 sequence and the preference for D in type IIa in the first amino acid of the hexamer could be noted. The repeats of 26 amino acids showed greater variations, probably due to the higher sequence number analysed. The Two Sample Logo consists of stacks of symbols: one stack for each position in the sequence, the upper part represents type I proteins preference for one amino acid in a given position with respect to type IIa amino acid at the same position and vice versa in the lower part. The overall height of the stack indicates the sequence conservation at that position, while the height of symbols within the stack indicates the relative frequency of each amino acid at that position. Amino acids are coloured according to their chemical properties: polar amino acids (G,S,T,Y,C,Q,N) are in green; basic (K,R,H) in blue; acidic (D,E) in red, and hydrophobic (A,V,L,I,W,F,M) amino acids are in black.