The Department is committed to research in the major areas of structural biology, investigating biological systems from the atomic to the cellular level of organization. The ultimate goal is to obtain a complete picture of biological structures in their complexity, with a continuity at all length scales, from _ngstroms to millimeters. The structure of biological macromolecules and their complexes is studied at the length scale of _ngstroms by X-ray diffraction from crystals, and in solution by advanced spectroscopic techniques such as nuclear magnetic resonance and EXAFS. Electron microscopy, electron tomography and atomic force miscroscopy are imaging techniques that span the range between nanometers and microns, from single molecules to macromolecular assemblies and whole tissue organization. The elucidation of the relations between structure and function of key components in main biological pathways is one of the generalized goals of the research conducted in the Department. One such pathway is the transcription of the genetic code from DNA to proteins. The research spans from analysis of the theoretical linguistic aspects of the code itself, to elucidation of the 3-D structure of DNA, and of DNA-protein complexes. The mechanism of translation of the code into proteins is investigated by X-ray crystallography in the structure of ribosomes, giant particles composed of RNA and more than 50 proteins, of tRNA synthetases and their complexes. Protein folding assisted by chaperones constitutes the last 'station' in the pathway. Structural and dynamical aspects of enzyme and protein function and recognition constitute another focal point of activity. Examples are studies on the mechanism of acetylcholinesterase, a key enzyme in the transmission of nerve impulse, of helicases in the unwinding of RNA, of proteins regulating membrane-fusion and virus entry into the cell, and of protein-saccharide complexes. Antibody-antigen recognition is studied through NMR, using the tools of molecular biology to unravel the energetic contributions of single interactions, and through antibodies interacting with monolayer and crystal surfaces. Studies on the relations between organic and mineral components and between structure, function and mechanical properties of mineralized tissues including bone, teeth, shells and many others, are performed over the whole range of hierarchical organizations. The development of new techniques in Archeological Chemistry provides information about human life conditions and technologies in prehistoric times. A new powerful 800MHz spectrometer is now in full operating conditions in the NMR laboratory; a major upgrade in the facilities for structural determination of biological macromolecules in solution has thus been achieved. A major upgrade is on the way in the electron microscopy facility, with the addition of two high resolution transmission electron microscopes and an environmental field emission scanning electron microscope.