Improvement of Hen Egg White Lysozyme Crystal Qualityby Control of Dehydration Process

Equal-thickness fringes that are attributed to the Pendellosung effect were clearly observed in the region of a tapered tetragonal hen egg white(HEW) lysozymecrystal with a wedge-like edge, which indicates that the misorientationbetween subgrains was on the order of 10−4°. This is attributed to control of the dehydration process for crystal growth from solution, which plays an important role. Both the local quality and whole homogeneity of the crystals were improved by regulating the dehydration process. Oscillatory contrast was observed in X-ray topographs from regions of the same thickness in the crystals (see Movie S1). However, the area of such contrast was quite small, which indicates the presence of defects, even in crystals for which equal-thickness fringes could be observed. We also discuss why the area of oscillatory contrast was small for tetragonal HEW lysozymecrystals with misorientationsbetween subgrains on the order of 10−4°.