Crystal structure of recombinant pea cytosolic ascorbate peroxidase.

Patterson, W.R.; Poulos, T.L.

doi:10.2210/pdb1apx/pdb

Macromolecule Content

Total Structure Weight: 111012.59
Atom Count: 7836
Residue Count: 996
Unique protein chains: 1

1APX

CRYSTAL STRUCTURE OF RECOMBINANT ASCORBATE PEROXIDASE

DOI: 10.2210/pdb1APX/pdb

Classification: PEROXIDASE
Organism(s): Pisum sativum
Expression System: Escherichia coli

Deposited: 1995-02-01 Released: 1996-03-08
Deposition Author(s): Patterson, W.R., Poulos, T.L.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 2.2 Å
R-Value Work: 0.193

wwPDB Validation3D Report Full Report

This is version 1.3 of the entry. See complete history.

Literature

Crystal structure of recombinant pea cytosolic ascorbate peroxidase.

Patterson, W.R., Poulos, T.L.

(1995) Biochemistry 34: 4331-4341

PubMed: 7703247 Search on PubMed
Primary Citation of Related Structures:
1CCK

PubMed Abstract:

The crystal structure of recombinant pea cytosolic ascorbate peroxidase has been refined to an R = 0.19 for data between 8.0 and 2.2 A resolution and magnitude of F > or = 2 sigma(magnitude of F). The refined model consists of four ascorbate peroxidase monomers consisting of 249 residues per monomer assembled into two homodimers, with one heme group per monomer. The ascorbate peroxidase model confirms that the pea cytosolic enzyme is a noncovalent homodimer held together by a series of ionic interactions arranged around the 2-fold noncrystallographic dimer axis. As expected from the high level of sequence identity (33%), the overall fold of the ascorbate peroxidase monomer closely resembles that of cytochrome c peroxidase. The average root mean square differences for 137 helical alpha-carbon atoms between the four ascorbate peroxidase monomers and cytochrome c peroxidase and for 249 topologically equivalent alpha-carbon atoms are 0.9 and 1.3 A, respectively. The active site structures are also the same, including the hydrogen-bonding interactions between the proximal His ligand, a buried Asp residue, and a Trp residue, whose indole ring is parallel to and in contact with the proximal His ligand just under the heme ring. This proximal Trp residue is thought to be the site of free radical formation in cytochrome c peroxidase compound I and is also essential for enzyme activity. The corresponding Trp in ascorbate peroxidase, Trp179, occupies exactly the same position. The most interesting, and possibly functionally important, difference between the two peroxidases is the presence of a cation binding site in ascorbate peroxidase located approximately 8 A from the alpha-carbon atom of Trp179.

Related Citations:

Characterization and Crystallization of Recombinant Pea Cytosolic Ascorbate Peroxidase
Patterson, W.R.,Poulos, T.L.
(1994) J.Biol.Chem. 269: 17020

Organizational Affiliation:

Department of Physiology and Biophysics, University of California, Irvine 92717, USA.

Macromolecules

Find similar proteins by: Sequence | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
CYTOSOLIC ASCORBATE PEROXIDASE	A, B, C, D	249	Pisum sativum	Mutation(s): 0 Gene Names: APX1 (APPX1) EC: 1.11.1.11
Find proteins for P48534 (Pisum sativum) Go to UniProtKB: P48534
Protein Feature View Full Protein Feature View for P48534

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions	3D Interactions
K Query on K Download SDF File Download CCD File	A, B, C, D	POTASSIUM ION K NPYPAHLBTDXSSS-UHFFFAOYSA-N		Ligand Interaction
HEM Query on HEM Download SDF File Download CCD File	A, B, C, D	PROTOPORPHYRIN IX CONTAINING FE HEME C₃₄ H₃₂ Fe N₄ O₄ KABFMIBPWCXCRK-RGGAHWMASA-L		Ligand Interaction