A novel handling-free method of mounting single protein crystals for synchrotron structure analyses at room temperature

Abstract

We have developed a handling-free mounting method for X-ray crystallography of protein crystals at room temperatures—the glass capillary method. In this method, crystals were nucleated and grown on the capillary walls, and then, growth solutions were gently removed. The procedures for collecting data on the crystals were conducted by simply setting the capillary on the goniometer of a synchrotron beamline without touching the crystals. Crystal quality was characterized using mosaicity, resolution at I/σ(I) = 2, I/σ(I) at resolution = 2.0 Å, Rmerge, and completeness. Wilson plots were also used to characterize the quality of crystals. In particular, all samples showed very low mosaicity; the handling-free method successfully retained their low mosaicity and effectively maintained the crystal quality.

Precipitant-Free Crystallization of Lysozyme and Glucose Isomerase by Drying

“…The drying process in glass capillary or in hanging-drops on glass slides under adequate humidity conditions would be favorable, as we could mount crystals without touching them for both processes. Actually, we have already developed a handling-free mounting method using glass capillaries for X-ray crystallography of protein crystals at ambient temperature [12]. Although Ghatak et al showed that lysozyme and proteinase K seemed to be crystallized by the evaporation of water at 20 • C, they argued that the crystals were obtained due to the effects of an incision on plasma oxidized polydimethylsiloxane substrate; they claimed that crystals were not obtained by concentration of proteins by evaporation of water.…”