Observation of dislocations in hen egg-white lysozyme crystals by synchrotron monochromatic-beam X-ray topography

Dislocations in large hen egg-white lysozyme (HEWL) crystals with tetragonal and orthorhombic forms were investigated by means of synchrotron monochromatic-beam X-ray topography. For the tetragonal form, not only screw dislocations but also edge ones are found to be included in predominant ones parallel to < 110 > directions. In addition, curved dislocations that can be related to (001)< 110 > slip system are observed at the crystal edges. For the orthorhombic form, predominant edge dislocations with [001] Burgers vector are stereoscopically observed. It is clarified that they are generated at or around the nucleus centre or sector boundary. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim