BAG Barcelona is constituted by 9 groups that belong to the Institute of Molecular Biology Barcelona from the Spanish Research Council (IBMB-CSIC), the Institute for Research in Biomedicine (IRB), and the Research Institute from Hospital Santa Creu i Sant Pau (HSCSP-IR). The main subjects of research are protein/DBA complexes, molecular machines, compounds of viruses, and the molecular mechanisms of proteases and other enzymes. Our Scientific results strongly rely on the high quality data and excellent performance and support of ESRF macromolecular crystallography beamlines.