Figure 4
From: Evolutionarily conserved bias of amino-acid usage refines the definition of PDZ-binding motif
Biased AA usages in the PB motifs located at the C-terminal ends of proteins. Each grid indicates the AAs providing significantly lower C-indexes when placed at the positions -4, -3 or -1 in the three-position-specified PB motifs, relative to the two-position-specified PB motifs. The three colors represent positions (-4: green,-3: red, and -1: yellow). (a-h) Six and two variants of type-I (a-f) and type-II (g and h)PB motifs. Each panel contains three major columns that represent three positions (-4,-3, -1). These "position" columns are subdivided into five columns that represent the five species examined (h, human; m, mouse; z, zebrafish; f, fruit fly; n, nematode).Twenty AAs are arranged vertically in single letter code.