PDBsum entry 1a7u

Haloperoxidase

PDB id: 1a7u

Contents

Protein chains

277 a.a. *

Waters ×399

* Residue conservation analysis

PDB id:

1a7u

Name:

Haloperoxidase

Title:

Chloroperoxidase t

Structure:

Chloroperoxidase t. Chain: a, b. Synonym: haloperoxidase t. Engineered: yes

Source:

Streptomyces aureofaciens. Organism_taxid: 1894. Strain: tue24. Gene: cpot. Expressed in: streptomyces lividans. Expression_system_taxid: 1916.

Biol. unit:

Trimer (from PQS)

Resolution:

1.75Å R-factor: 0.149 R-free: 0.176

Authors:

B.Hofmann,S.Toelzer,I.Pelletier,J.Altenbuchner,K.-H.Van Pee,H.- J.Hecht

Key ref:

B.Hofmann et al. (1998). Structural investigation of the cofactor-free chloroperoxidases. J Mol Biol, 279, 889-900. PubMed id: 9642069 DOI: 10.1006/jmbi.1998.1802

Date:

17-Mar-98 Release date: 17-Jun-98

Protein chains

O31168  (PRXC_KITAU) -  Non-heme chloroperoxidase from Kitasatospora aureofaciens

Seq: 278 a.a.

Struc: 277 a.a.

Enzyme reactions

• Enzyme class: E.C.1.11.1.- - ?????

DOI no: 10.1006/jmbi.1998.1802

J Mol Biol 279:889-900 (1998)

PubMed id: 9642069

Structural investigation of the cofactor-free chloroperoxidases.

B.Hofmann, S.Tölzer, I.Pelletier, J.Altenbuchner, K.H.van Pée, H.J.Hecht.

ABSTRACT

The structures of cofactor-free haloperoxidases from Streptomyces aureofaciens, Streptomyces lividans, and Pseudomonas fluorescens have been determined at resolutions between 1.9 A and 1.5 A. The structures of two enzymes complexed with benzoate or propionate identify the binding site for the organic acids which are required for the haloperoxidase activity. Based on these complexes and on the structure of an inactive variant, a reaction mechanism is proposed for the halogenation reaction with peroxoacid and hypohalous acid as reaction intermediates. Comparison of the structures suggests that a specific halide binding site is absent in the enzymes but that hydrophobic organic compounds may fit into the active site pocket for halogenation at preferential sites.

Selected figure(s)

Figure 3.
Figure 3. Stereo picture of the electron density of the substrate complexes. The coordinates of the substrate molecules benzoic acid and propionic acid were left out of the entire refinement and all map calculations in order to reduce model bias. The density of the (2F[obs]−F[calc]) map is contoured at the 1.0 σ level and colored green, the density of the (F[obs]–F[calc]) difference map is contoured at the 4.0 σ level and colored blue. (a) Stereo picture of the electron density for the complex of CPO-T with benzoate. Residual electron density at Ser98 indicates the alternative, lower occupancy, side-chain conformation. (b) Stereo picture of the electron density for the complex of CPO-F with propionate.

Figure 4.
Figure 4. Stereo picture of the active site of the Met99Thr variant of CPO-A2. (a) Stereo picture of the electron density showing the bound chloride ion and the side-chain conformation of Thr99 in the variant. The density of the (2F[obs]–F[calc]) map is contoured at the 1.0 σ level. (b) Stereo picture of a superimposition of wild-type CPO-L (C^α trace and carbon atoms colored dark gray) on the variant (C^α trace colored red and carbon atoms colored yellow). The chloride ion is colored magenta. The chloride ion is colored magenta.

The above figures are reprinted by permission from Elsevier: J Mol Biol (1998, 279, 889-900) copyright 1998.

Figures were selected by an automated process.