CRYSTAL-STRUCTURES OF BILE-SALTS - SODIUM TAUROCHOLATE

Crystals of sodium taurocholate (NaC26H44NO7S.2.5H2O) belonging to the triclinic space group P1 have unit cell parameters a = 12.731 (2), b = 16.104 (2), c = 7.628 (1) angstrom, alpha = 83.40 (1), beta = 101.20 (1), gamma = 105.35 (1)-degrees, and two molecules in the asymmetric unit. The refinement, carried out on 4424 observed reflections, gave R = 0.059 and R(w) = 0.066. The packing is characterized by bilayers, formed by antiparallel monolayers and with nonpolar outermost surfaces, held together by van der Waals interactions. Inside the bilayers there are channels, lined with the polar groups, and filled by sodium ions and water molecules. A structural unit has been identified that could provide a reasonable model for the micellar aggregates of this bile salt.