Unusual cyanide bindings to a heme-regulated phosphodiesterase from Escherichia coli: Effect of Met95 mutations

Miki Watanabe, Toshitaka Matsui, Yukie Sasakura, Ikuko Sagami, Toru Shimizu

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

In order to understand heme environment of a heme-regulated phosphodiesterase (Ec DOS), the binding behavior of cyanide to the Fe (III) complex was examined. Interestingly, the rate of cyanide binding to full-length Ec DOS was unusually slow with kon = 0.0022mM-1 s-1, while the rate for the isolated heme domain of Ec DOS (0.045mM-1 s-1) was 20-fold higher. Ala and Leu mutations at Met95, which has been suggested to be a heme axial ligand, increased the kon rate 11- and 8-fold, respectively, and dramatically decreased the cyanide dissociation rate from the isolated heme domain. His mutation at Met95, on the other hand, caused a 17-fold decrease in the kon value. We discuss the unusual cyanide binding behavior and the role of Met95 in controlling cyanide binding.

Original languageEnglish
Pages (from-to)169-172
Number of pages4
JournalBiochemical and biophysical research communications
Volume299
Issue number2
DOIs
Publication statusPublished - 2002

Keywords

  • Axial ligand
  • Cyanide
  • Heme sensor
  • Optical absorption
  • Phosphodiesterase
  • Site-directed mutagenesis

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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