A major challenge for Biology in the 21^st century is to reach the quantitative level of Physics and Chemistry. Following this trend, the main research goal of CPB is to develop a quantitative understanding of specific biological problems at different levels of complexity, from the single molecule level to sub-cellular macromolecular assemblies. This knowledge will enable to predict, control and engineer essential biological functions towards biomedical and/or biotechnological applications. In order to meet these challenges, CPB line gathers a powerful combination of strengths in Structural Biology, Mechanistic Biochemistry, Molecular Biophysics, and Computational Biology that is organized in two sublines: i) Structural and Quantitative Biology and ii) Biomolecular Recognition and Assembly. Methodologically, research at CPB involves the combination of physical chemical and biological methods to attain high-resolution structural, temporal and ensemble (single molecule versus collective behavior) information of the molecular events controlling biological phenomena with well-established expertise in the identification, isolation, quantitative characterization, modification, and engineering of peptides, proteins and macromolecular assemblies involved in essential cellular processes. CPB research efforts range from fundamental processes (such as protein structure, folding, aggregation and evolution, protein function and regulation, energetics and dynamics of biomolecular interactions), to more applied efforts towards developing new substances with pharmacological interest, such as new antibiotics. These projects cover from the structural and functional analysis of specific biological problems (such as DNA replication and repair, cell division, cancer, angiogenesis, antibiotic action and resistance, programmed cell-death, post-translational modifications, and chromatin structure) to the in vitro reconstitution and engineering of sub-cellular macromolecular machines.  The CPB line aims to combine these research efforts and multidisciplinary expertise into a common structure fostering collaboration within CPB and with other researchers at CIB and outside, and optimization of the large-scale instrument infrastructure required for this research.