A possible helical model for sodium glycocholate micellar aggregates

Sodium glycocholate crystallizes in the tetragonal space group I4 with a = b = 27.793(4), c = 7.937(1) angstrom, and Z = 8. Refinement based on 2290 observed reflections led to a conventional R = 0.10. The bile salt molecules are arranged in a helix with 2(1) symmetry stabilized mainly by polar interactions. Four helices are held together by hydrogen bonds involving water molecules, giving rise to hydrophilic channels, with a small cross section, which can include water molecules. The packing of these tetramers form hydrophobic channels containing some disordered acetone and water molecules. The helices will be checked as a model for the micellar aggregates of this important conjugated bile salt, following the same strategy successfully applied to sodium deoxycholate.