Structure and growth of ultrasmall protein microcrystals by synchrotron radiation: II. microGISAX and microscopy of lysozyme.

The early steps of growth and nucleation of the lysozyme microcrystals by classical and nanotemplate-based hanging vapor diffusion methods are studied using microGISAXS at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Out-of-plane cuts in the Yoneda regions of the 2D scattering profiles point to the detection of ultrasmall lysozyme crystals by microGISAXS quite before than by light microscopy. Furthermore lysozyme crystal formation occurs quite earlier with the nanotemplate than with the classical method. Our data are compatible with two distinct modes of crystal nucleation and growth for P450sc and lysozyme.