Direct observation of ultrafast collective motions in CO myoglobin upon ligand dissociation

Science. 2015 Oct 23;350(6259):445-50. doi: 10.1126/science.aac5492. Epub 2015 Sep 10.

Abstract

The hemoprotein myoglobin is a model system for the study of protein dynamics. We used time-resolved serial femtosecond crystallography at an x-ray free-electron laser to resolve the ultrafast structural changes in the carbonmonoxy myoglobin complex upon photolysis of the Fe-CO bond. Structural changes appear throughout the protein within 500 femtoseconds, with the C, F, and H helices moving away from the heme cofactor and the E and A helices moving toward it. These collective movements are predicted by hybrid quantum mechanics/molecular mechanics simulations. Together with the observed oscillations of residues contacting the heme, our calculations support the prediction that an immediate collective response of the protein occurs upon ligand dissociation, as a result of heme vibrational modes coupling to global modes of the protein.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Carbon Monoxide / chemistry
  • Crystallography, X-Ray
  • Heme / chemistry
  • Horses
  • Iron / chemistry
  • Ligands
  • Molecular Dynamics Simulation
  • Motion
  • Myoglobin / chemistry*
  • Photolysis
  • Protein Structure, Secondary

Substances

  • Ligands
  • Myoglobin
  • carboxymyoglobin
  • Heme
  • Carbon Monoxide
  • Iron

Associated data

  • PDB/5CMV
  • PDB/5CN4
  • PDB/5CN5
  • PDB/5CN6
  • PDB/5CN7
  • PDB/5CN8
  • PDB/5CN9
  • PDB/5CNB
  • PDB/5CNC
  • PDB/5CND
  • PDB/5CNE
  • PDB/5CNF
  • PDB/5CNG
  • PDB/5D5R