Nanoworld Institute, University of Genoa, Corso Europa 30, 16132 Genoa, Italy
During a recent stage at the European Synchrotron Radiation Facility and European Molecular Biology Laboratory in Grenoble, France, few new trends in protein nanocrystallography [1-4] have been emerging. First of all, new details in protein crystal topography appear evident from AFM experimentations. The obtained images point to the existence of clear domains in the crystal 3D organization, quite pronounced and different in size and number between the classical protein crystals and the crystals grown by LB (Langmuir-Blodgett) protein nanotemplate. This result is furthermore in perfect accordance with what obtained by the laser cutting of the corresponding protein crystals down to the nanosize and along the crystal domains. X-ray diffraction with highly focused synchrotron radiation down to 500 nm diameter strikingly provides unique and detailed atomic structure information in protein microcrystals down to the submicron size in several model systems, opening new avenues in protein crystallography.
With radiation damage being the most critical issue for the protein structure determination at the intense synchrotron radiation, LB crystals were indeed confirmed as the most stable to radiation damage in a wide range of model systems. Crystals grown by nanotemplate still diffracts at good resolution even after several steps of X-ray "burning", while the classical crystals decay very quickly at the same exposure. Finally due to this encouraging results, the LB method has also been successfully adapted to the EMBL advanced robotics system for protein crystallography.