A peptide's perspective of water dynamics

► 2D IR spectroscopy reveals the vibrational frequency dynamics of protein amide I modes from nearby water molecules. ► The evolution of the shape of the 2D IR spectra of aqueous amides characterizes the amide vibrational frequency correlations. ► Benchmarks for interpreting 2D IR spectra of complex biomolecules are thereby created. ► In one example the dynamics of water molecules confined in a viral proton channel are examined. ► In another, the water in fibrils is revealed by the 2D IR spectral shape evolution.