Tunneling in ligand binding to heme proteins

Academic Article


  • 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.
  • Authors

    Published In

  • Science  Journal
  • Digital Object Identifier (doi)

    Author List

  • Alberding N; Austin RH; Beeson KW; Chan SS; Eisenstein L; Frauenfelder H; Nordlund TM
  • Start Page

  • 1002
  • End Page

  • 1004
  • Volume

  • 192
  • Issue

  • 4243