The building blocks -- Motifs of protein structure -- Alpha-domain structures -- Alpha/beta structures -- Beta structures -- Folding and flexibility -- DNA structures -- DNA recognition in procaryotes by helix-turn-helix motifs -- DNA recognition by eucaryotic transcription factors -- Specific transcription factors belong to a few families -- An example of enzyme catalysis : serine proteinases -- Membrane proteins -- Signal transduction -- Fibrous proteins -- Recognition of foreign molecules by the immune system -- The structure of spherical viruses -- Prediction, engineering, and design of protein structures -- Determination of protein structures.