Time-resolved resonance Raman study on ultrafast structural relaxation and vibrational cooling of photodissociated carbonmonoxy myoglobin

Teizo Kitagawa, Nami Haruta, Yasuhisa Mizutani

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

A localized small structural change is converted to a higher order conformational change of protein and extends to a mesoscopic scale to induce a physiological function. To understand such features of protein, ultrafast dynamics of myoglobin (Mb) following photolysis of carbon monoxide were investigated. Recent results are summarized here with a stress on structural and vibrational energy relaxation. The core expansion of heme takes place within 2 ps but the out of plane displacement of the heme iron and the accompanying protein conformational change occur in 10 and 100 s of the picosecond regimes, respectively. Unexpectedly, it was found from UV resonance Raman spectra that Trp7 in the N-terminal region and Tyr151 in the C-terminal region undergo appreciable structural changes upon ligand binding-dissociation while Tyr104, Tyr146, and Trp14 do not. Because of the communication between the movements of these surface residues and the heme iron, the rate of spectral change of the iron-histidine (Fe-His) stretching band after CO photodissociation is influenced by the viscosity of solvent. Temporal changes of the anti-Stokes Raman intensity demonstrated immediate generation of vibrationally excited heme upon photodissociation and its decay with a time constant of 1-2 ps.

Original languageEnglish
Pages (from-to)207-213
Number of pages7
JournalBiopolymers - Biospectroscopy Section
Volume67
Issue number4-5
DOIs
Publication statusPublished - 2002 Jul 11
Externally publishedYes

Keywords

  • Photodissociated carbonmonoxy myoglobin
  • Time-resolved resonance Raman spectroscopy
  • Ultrafast structural relaxation
  • Vibrational cooling

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Biomaterials
  • Organic Chemistry

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