2QFN

X-ray Crystal Structure Analysis of the Binding Site in the Ferric and Oxyferrous Forms of the Recombinant Heme Dehaloperoxidase Cloned from Amphitrite ornata

Summary for 2QFN

• Entry DOI: 10.2210/pdb2qfn/pdb
• Related: 2QFK
• Descriptor: Dehaloperoxidase A, AMMONIUM ION, SULFATE ION, ... (6 entities in total)
• Functional Keywords: dehaloperoxidase, dhp, globin, heme protein, transport protein
• Biological source: Amphitrite ornata
• Total number of polymer chains: 2
• Total formula weight: 32948.69

Authors

de Serrano, V.,Chen, Z.,Davis, M.F.,Franzen, S. (deposition date: 2007-06-27, release date: 2008-05-20, Last modification date: 2024-02-21)

Primary citation

de Serrano, V.,Chen, Z.,Davis, M.F.,Franzen, S.
X-ray crystal structural analysis of the binding site in the ferric and oxyferrous forms of the recombinant heme dehaloperoxidase cloned from Amphitrite ornata
Acta Crystallogr.,Sect.D, 63:1094-1101, 2007

PubMed Abstract: The dehaloperoxidase (DHP) from the terebellid polychaete Amphitrite ornata is an enzyme that converts para-halogenated phenols to the corresponding quinones in the presence of hydrogen peroxide. Its enzymatic activity is similar to that of heme peroxidases such as horseradish peroxidase, yet it has the structural characteristics of the globin family of proteins, the main functions of which are oxygen transport and storage. In order to investigate the dual function of this hemoglobin peroxidase, the enzyme was expressed in Escherichia coli as a recombinant protein in its wild-type form and as a mutant protein in which Cys73 was replaced by a serine residue (C73S). Both the wild-type and mutant proteins were crystallized and their structures were determined at 100 K to a resolution of 1.62 A. The structure of the wild-type protein demonstrated that it was in the metaquo form, with the heme iron in the ferric oxidation state and the bound water lying 2.2 A from the heme iron. The structure of the C73S mutant protein was shown to contain a ferrous heme iron with a bound oxygen molecule. The bent bonding geometry of the Fe-O(1)-O(2) adduct results in a hydrogen bond of length 2.8 A between the second O atom, O(2), of molecular oxygen and N(2) of the distal histidine residue (His55) in both subunits contained within the asymmetric unit. This hydrogen-bonding interaction between His55 and the bound diatomic oxygen molecule provides new insight into the catalytic activation of H(2)O(2), which is essential for peroxidase activity.

PubMed: 17881827
DOI: 10.1107/S0907444907043417

Experimental method

X-RAY DIFFRACTION (1.62 Å)