HDX opening energies and model assumptions
Research context
research method · established · As of 2026-10-10
In the EX2 opening model, exchange rates constrain approximate opening free energies.
Key knowledge
In the EX2 opening model, exchange rates constrain approximate opening free energies. Intact-domain mHDX-MS infers a distribution of rates without assigning each rate to a sequence position; estimated chemical rates and back exchange contribute uncertainty.
Values and equations
DeltaG_open = R*T*ln(k_chem/k_HX - 1)
- DeltaG_open
- molar opening free energy J mol^-1
- R
- gas constant J mol^-1 K^-1
- T
- temperature K
- k_chem
- estimated open-state chemical exchange rate s^-1
- k_HX
- measured/inferred hydrogen-exchange rate s^-1
Conditions and scope
- Assumes equilibrium/first-order independent exchanges, positive temperature and 0 < k_HX < k_chem for the displayed inverse EX2 free-energy expression; combining pH 6/9 assumes unchanged landscape, and equal back-exchange probabilities are an approximation.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Large-scale discovery, analysis and design of protein energy landscapes: mHDX-MS equations (1)–(5), EX2/pH/back-exchange assumptions and NMR validation (full relevant original method/results sections)
2026-10-10 · Bounded author source inspection of hdx opening energies and model assumptions, including the stated conditions; independent branch review is recorded separately.
Entry details
Permanent link to this entry ↗- Record identity
- res-bio-hdx-opening
- Revision
- research.1
- Structured reference record
- Postgraduate & research reference