1c8i

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Revision as of 10:08, 20 November 2007

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spinqualitylabelsall models 1c8i, resolution 2.0Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

BINDING MODE OF HYDROXYLAMINE TO ARTHROMYCES RAMOSUS PEROXIDASE

Overview

The interaction of hydroxylamine (HA) with Arthromyces ramosus peroxidase, (ARP) was investigated by kinetic, spectroscopic, and x-ray, crystallographic techniques. HA inhibited the reaction of native ARP with, H(2)O(2) in a competitive manner. Electron absorption and resonance Raman, spectroscopic studies indicated that pentacoordinate high spin species of, native ARP are converted to hexacoordinate low spin species upon the, addition of HA, strongly suggesting the occurrence of a direct interaction, of HA with ARP heme iron. Kinetic analysis exhibited that the apparent, dissociation constant is 6.2 mm at pH 7.0 and that only one HA molecule, likely binds to the vicinity of the heme. pH dependence of HA binding, suggested that the nitrogen atom of HA could be involved in the, interaction with the heme iron. X-ray crystallographic analysis of ARP in, complex with HA at 2.0 A resolution revealed that the electron density, ascribed to HA is located in the distal pocket between the heme iron and, the distal His(56). HA seems to directly interact with the heme iron but, is too far away to interact with Arg(52). In HA, it is likely that the, nitrogen atom is coordinated to the heme iron and that hydroxyl group is, hydrogen bonded to the distal His(56).

About this Structure

1C8I is a Single protein structure of sequence from Eukaryota with BMA, CA, HEM and HOA as ligands. Active as Peroxidase, with EC number 1.11.1.7 Full crystallographic information is available from OCA.

Reference

Direct binding of hydroxylamine to the heme iron of Arthromyces ramosus peroxidase. Substrate analogue that inhibits compound I formation in a competetive manner., Wariishi H, Nonaka D, Johjima T, Nakamura N, Naruta Y, Kubo S, Fukuyama K, J Biol Chem. 2000 Oct 20;275(42):32919-24. PMID:10915789

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