The potential usefulness of the new zwitterionic solubilizing agent, d
imethyl ethylammonium propane sulfonate (NDSB195), in protein crystall
ization was shown using hen egg-white lysozyme. In the presence of thi
s agent, highly diffracting crystals were obtained using ammonium sulp
hate as a precipitant, whereas in its absence only amorphous precipita
tes were obtained. The crystals possess a triclinic unit cell not prev
iously described and diffract to a resolution of 2 Angstrom. To ascert
ain that the new reagent had not produced significant changes in the p
rotein fold the structure was determined to a resolution of 2.6 Angstr
om. Only minor differences were observed (notably in regions of crysta
l contacts) with the known tetragonal lysozyme structure (Brookhaven P
rotein Data Bank entry 1HEL).