%0 Journal Article %T Harry Potter and the structural biologist's (Key)stone %A Damien Devos %A Olga V Kalinina %A Robert B Russell %J Genome Biology %D 2006 %I BioMed Central %R 10.1186/gb-2006-7-12-333 %X After the first Keystone symposium held outside America, which took place in October 2005 in Singapore, the first in Europe was held at St John's College, Cambridge, UK. As stated by one of the speakers and clearly felt by many others, the venue of St. John's College gave a real 'Harry Potter' feeling to the conference, which brought together a multi-disciplinary group of scientists interested in structures of large protein complexes and in how structural insights can aid understanding of cell regulation.Cells are giant, highly dynamic molecular assemblies. They contain thousands of protein complexes, the molecular machines that carry out most of the textbook biological processes, from DNA replication to metabolism. These machines are themselves highly regulated and dynamic, and this regulation is carried out by a host of signaling processes mediated, in turn, by a great variety of protein interactions. The conference saw contributions covering all aspects of cell structure and regulation, from the atomic to the cellular level, and with subjects ranging from methods for solving structures to applications of hybrid approaches for the elucidation of structural aspects of biological processes.Wolfgang Baumeister (Max Planck Institute for Biochemistry, Martinsried, Germany) presented a global vision of the cell derived from a combination of proteomics and electron tomography. Tomograms of cells at molecular resolution are essentially three-dimensional images of the cell's entire proteome and reveal the spatial relationships of macromolecules directly. Approaching 3 nm in resolution, they provide a fascinating insight into the principles of supramolecular organization and a basis for studying higher cellular functions. These tomograms have a fundamental problem, however: very often one does not know what one is looking at. To get around this, Baumeister and colleagues are assembling a molecular atlas of large complexes determined by X-ray or electron microscopy (EM) meth %U http://genomebiology.com/2006/7/12/333