Vr. Samygina et al., Improving the X-ray resolution by reversible flash-cooling combined with concentration screening, as exemplified with PPase, ACT CRYST D, 56, 2000, pp. 595-603
A significant improvement in the X-ray resolution of crystals of Escherichi
a coli inorganic pyrophosphatase at cryo-temperature was obtained as a resu
lt of studying the relationship between the crystal order and cryosolution
component concentrations. To perform the experiments, the ability to revers
e the flash-cooling process and to return a crystal to ambient temperature
was used. In each cycle, the crystal was transferred from a cold nitrogen-g
as stream to a cryosolution with modified concentrations of the components.
The crystal was then flash-cooled again and the diffraction quality checke
d. Such a technique allows the screening of a wide concentration range rath
er quickly without using a large number of crystals and allows the determin
ation of optimal cryosolution component concentrations. The resolution limi
t for crystals of pyrophosphatase increased by almost 0.7 Angstrom, from 1.
8 to 1.15 Angstrom.