Role of Thiolate Ligand in Spin State and Redox Switching in the Cytochrome P450 Catalytic Cycle

Hiroshi Suzuki, Kanako Inabe, Yoshinori Shirakawa, Naoki Umezawa, Nobuki Kato, Tsunehiko Higuchi

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The catalytic cycle of cytochrome P450 involves a change from the resting-state, water-bound, six-coordinated form (1, low-spin state) to a five-coordinated form (2, high-spin state) upon binding of a hydrophobic substrate. Here, we used a heme-thiolate model complex (SR complex) with THF as a model of nonionic H2O to address the question of whether or not coordination of nonionic water is sufficient to induce the low-spin state. Measurements of electronic absorption spectra and magnetic properties confirmed that five-coordinated SR complex has a high-spin state, and THF-bound, six-coordinated SR has a low-spin state in dichloromethane at ambient temperature. The redox potential E1/2 (FeII/FeIII) of THF-bound SR was 80-90 mV more negative than that of five-coordinated SR. These properties indicate SR is a good model of P450. Our results suggest that thiolate coordination plays a key role in setting the low energy barrier between the high-spin and low-spin states.

Original languageEnglish
Pages (from-to)4245-4248
Number of pages4
JournalInorganic chemistry
Volume56
Issue number8
DOIs
Publication statusPublished - 2017 Apr 17
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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