Conformational adaptability of disulfatide headgroups. (a) Superimposed ligand conformations in open and closed dimers (crystal forms 1 and 2, respectively) of wtGLTP. Protein moieties were superposed and skipped. Disulfatide molecules are shown in stick representation; colour codes for O, N and S atoms are red, blue and green, respectively. C atoms are coloured magenta for crystal form 1 and pink for crystal form 2. (b) Disulfatide conformations in two crystal forms (1 and 4; Tables 1 and 2) of D48V. C atoms are coloured cyan for crystal form 1 and light cyan for crystal form 4. Colour codes for other atoms are as in (a). (c, d) Disulfatide in the open dimer of wtGLTP versus the two conformations of disulfatide shown in (b).