Year: 2026
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Hydrogen–deuterium exchange (HDX) of protein backbone amides provides a powerful probe of conformational dynamics. However, when experiments are performed in H 2 O/D 2 O mixtures, quantitative interpretation is hindered by back exchange and isotope effects not captured by the classical Linderstro̷m–Lang (LL) model. We introduce a generalized Linderstro̷m–Lang (GLL) framework that explicitly accounts for forward and reverse exchange and for changes in protection upon isotopic substitution. Analytical solutions describe equilibrium enrichment (fractionation) and protection factors in mixtures, reducing to the LL model in pure D 2 O. Application to HDX/NMR of the molecular chaperone DNAJB1 in 50% D 2 O demonstrates that the GLL model recovers protection factors at 100% D 2 O. Ignoring back exchange (i.e., using the LL model), protection factors are systematically underestimated. A particularly powerful feature of our approach is that a single HDX experiment in a mixture (e.g., 50% D 2 O) simultaneously provides protection factors that report on conformational dynamics and local stability and fractionation factors that are sensitive to the local hydrogen-bonding environment.
Source: ACS Physical Chemistry Au
Institutions: University of Bologna, Imperial College London
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,500
OpenAlex ID: W7138156486