ATR-FTIR spectroscopy monitors protein reactions and interactions of monolayers at the atomic level. On p. 2649 K. Gerwert, C. Kötting et al. describe a method to immobilize proteins by means of a polyhistidine-tag and nitrilotriacetic-acid-modified lipids. Because polyhistidine tags are often used for protein purification, modified proteins are easy to access. This makes the method a universal technique for many soluble proteins. The setup allows the investigation of the secondary structure, orientation, reaction mechanisms and protein–ligand or protein–protein interactions.