Inertial water response dominates protein solvation dynamics

Abstract Establishing the mechanism of protein folding and other physiological processes requires a detailed comprehension of protein-solvent interactions. The fastest protein solvation dynamics have not yet been thoroughly investigated due to challenges associated with controlling few-cycle laser pulses and identifying ideal model systems. Here we use 6 fs laser pulses to quantify the sub-picosecond solvation dynamics of an engineered pigment-protein complex that serves as an ideal probe of solvation dynamics. The data reveal that protein solvation dynamics are described well by a single lifetime of 33 fs, indicating that the mechanism of protein solvation is dominated by the inertial water component.