Pentacoordination of the heme iron of Arthromyces ramosus peroxidase shown by a 1.8 Å resolution crystallographic study at pH 4.5

  • Kunishima N
  • Amada F
  • Fukuyama K
 et al. 
  • 4

    Readers

    Mendeley users who have this article in their library.
  • 45

    Citations

    Citations of this article.

Abstract

In the presence of ammonium sulfate the absorption spectra of a peroxidase from the fungus Arthromyces ramosus (ARP) showed that the low-spin component increased as the pH increased from 6.0 to 9.0, whereas in its absence ARP remained in the high-spin state in the pH range investigated. The crystal structure of ARP at pH 4.5 in the presence of ammonium sulfate at 1.8 A resolution showed that the electron density at the 6th position of the heme iron seen at pH 7.5 had disappeared and that the iron atom deviated markedly from the heme plane. These observations strongly suggest that under physiological conditions the heme of ARP is in the pentacoordinated high-spin state and that at a high pH the heme iron is able to bind ammonia, forming the low-spin state. The location of the water molecule at the distal side of the heme in peroxidases is also discussed.

Author-supplied keywords

  • Athromycex ramosus
  • Coordination of heme
  • Heme enzyme
  • Peroxidase
  • X-ray crystallography

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Naoki Kunishima

  • Fumiko Amada

  • Keiichi Fukuyama

  • Masahide Kawamoto

  • Takateru Matsunaga

  • Hiroshi Matsubara

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free