Water Penetration into Protein Secondary Structure Revealed by Hydrogen-Deuterium Exchange Two-Dimensional Infrared Spectroscopy

摘要

Hydrogen-deuterium exchange (HX) is a valuable tool for characterizing protein structural stability,solvation and water exposure,and unfolding kinetics.HX is influenced by the site-specific pK_a,solvent accessibility to protonated sites,and strength of hydrogen-bonding interactions.In the hydrophobic core or strongly hydrogen-bound secondary structures,HX rates are dramatically reduced due to shielding of exchangeable sites.NMR methods infer the degree of protection and structural stability from site-specific HX measurements,which can be incorporated into fast-mixing experiments to provide information about reaction intermediates.