Relationship between the electron density of the heme Fe atom and the vibrational frequencies of the fe-bound carbon monoxide in myoglobin

Ryu Nishimura, Tomokazu Shibata, Hulin Tai, Izumi Ishigami, Takashi Ogura, Satoshi Nagao, Takashi Matsuo, Shun Hirota, Kiyohiro Imai, Saburo Neya, Akihiro Suzuki, Yasuhiko Yamamoto

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We analyzed the vibrational frequencies of the Fe-bound carbon monoxide (CO) of myoglobin reconstituted with a series of chemically modified heme cofactors possessing a heme Fe atom with a variety of electron densities. The study revealed that the stretching frequency of Fe-bound CO (νCO) increases with decreasing electron density of the heme Fe atom (ρFe). This finding demonstrated that the νCO value can be used as a sensitive measure of the ρFe value and that the π back-donation of the heme Fe atom to CO is affected by the heme π-system perturbation induced through peripheral side chain modifications.

Original languageEnglish (US)
Pages (from-to)3349-3355
Number of pages7
JournalInorganic Chemistry
Issue number6
Publication statusPublished - Mar 18 2013
Externally publishedYes


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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