Missense mutations mapped onto DysF domain structure. (a and c) Ribbon representation showing W/R stack rotated 180 degrees about the y axis of the page; mutated residues implicated in stack formation (red), mutated residues in the surface (blue), mutated residues stabilising the arginines involved in stack formation (yellow). Other residues of the W/R stack are in green. (b): Interaction and environment of the most common pathogenic mutations (R959, W999 and R1046). H bonds shown as black dotted lines and stacking interactions as magenta dotted lines. Figure drawn with CCP4mg .