Direct observation of stress-induced dislocations in protein crystals by synchrotron X-ray topography

Stress-induced dislocations in glucose isomerase (GI) crystals were investigated by synchrotron X-ray topography with simple indentation method. It is observed that the indentation gives rise to the deformation associated with strain and dislocations over the entire crystal. It is characterized that three kinds of mobile dislocations with Burgers vectors of 1/2 < 111 >, < 100 > and < 010 > are at least introduced by the impact stresses due to the indentation. The shapes of the dislocations exhibit half loops and clusters of dislocation loops, as those in common inorganic crystals. It is suggested that the deformation in protein crystals also occurs by the dislocation mechanisms, as those in common inorganic crystals. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.