Preparation of single crystals of a yolk lipoprotein

Single crystals of a yolk lipoprotein from two species of lamprey oocytes have been prepared and shown to belong to the monoclinic space group C2. The unit cell dimensions combined with molecular weight determinations support the idea that the lipoprotein is a symmetrical dimer centered on a crystallographic 2-fold symmetry axis. The lipid content is estimated to be about 15% (w/w) and the crystals are suitable for structural studies by single crystal X-ray analysis. The X-ray results are correlated with those obtained by electron diffraction.