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Title: Observing heme doming in myoglobin with femtosecond X-ray absorption spectroscopy

We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a faster (~70 fs) relaxation preceding a slower (~400 fs) one. We tentatively attribute the first relaxation to a structural rearrangement induced by photolysis involving essentially only the heme chromophore and the second relaxation to a residual Fe motion out of the heme plane that is coupled to the displacement of myoglobin F-helix.
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [1] ;  [4]
  1. Univ. of Palermo, Palermo (Italy)
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  3. CNRS - Institut de Biologie Structurale, Grenoble 38044, France
  4. Univ. of Rennes, Rennes (France)
Publication Date:
OSTI Identifier:
1190858
Type:
Accepted Manuscript
Journal Name:
Structural Dynamics
Additional Journal Information:
Journal Volume: 2; Journal Issue: 4; Journal ID: ISSN 2329-7778
Publisher:
American Crystallographic Association/AIP
Research Org:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.