Cytochrome c oxidase: The influence of the "open-closed" transition on cytochrome a3

Denis L. Rousseau, Yuan Chin Ching, Sanghwa Han, Massimo Sassaroli, Satish Singh

Research output: Contribution to journalConference articlepeer-review


Cytochrome c oxidase is known to display a conformational transition from a "closed" to an "open" structure upon partial reduction. In the past exogenous ligand binding kinetic differences and differences in tryptophan fluorescence have been associated with this structural change. We report changes in the resonance Raman spectrum of NO-bound cytochrome as upon this transition. We detect changes in both the heme vibrational modes and in the Fe-N-O bending mode. Furthermore, we have been able to identify a hydroxide-bound intermediate in the enzyme. Analysis of the conditions for its generation lead to the proposal that it is stable only in the open conformation of the protein. In both of these series of experiments advantage was taken of the photoreducibility of the heme groups by the incident laser beam.

Original languageEnglish (US)
Pages (from-to)244-253
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Jul 5 1989
Externally publishedYes
EventRaman Scattering, Luminescence and Spectroscopic Instrumentation in Technology 1989 - Los Angeles, United States
Duration: Jan 15 1989Jan 20 1989

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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