Tunneling in ligand binding to heme proteins

N. Alberding, R. H. Austin, K. W. Beeson, S. S. Chan, L. Eisenstein, H. Frauenfelder, T. M. Nordlund

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Rebinding of carbon monoxide to the beta chain of hemoglobin after photodissociation by a laser flash is intramolecular below about 200 K. Above 25 K, rebinding occurs via classical over-the-barrier motion; below, quantum-mechanical tunneling dominates. Both are described by an energy spectrum peaked at EPeak=4.0 kilojoules per mole. The barrier width d(E), determined from the energy dependence of the tunneling rate, depends on barrier height, d(E) ≈ 0.05 nanometer × (E/Epeak)1.5.

Original languageEnglish (US)
Pages (from-to)1002-1004
Number of pages3
Issue number4243
StatePublished - Jan 1 1976
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General

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    Alberding, N., Austin, R. H., Beeson, K. W., Chan, S. S., Eisenstein, L., Frauenfelder, H., & Nordlund, T. M. (1976). Tunneling in ligand binding to heme proteins. Science, 192(4243), 1002-1004. https://doi.org/10.1126/science.1273579