Site-specific peptide probes detect buried water in a lipid membrane (Biophysical Journal)

Transmembrane peptides contain polar residues in the interior of the membrane, which may alter the electrostatic environment and favor hydration in the otherwise nonpolar environment of the membrane core. Here we demonstrate a general, non-perturbative strategy to probe hydration of the peptide backbone at specific depths within the bilayer using a combination of site-specific isotope labels, ultrafast two-dimensional infrared (2D IR) spectroscopy, and spectral modeling based on molecular dynamics simulations.