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Structure of dehaloperoxidase B at 1.58 Å resolution and structural characterization of the AB dimer from Amphitrite ornata

Journal Article · · Acta Crystallogr. D
As members of the globin superfamily, dehaloperoxidase (DHP) isoenzymes A and B from the marine annelid Amphitrite ornata possess hemoglobin function, but they also exhibit a biologically relevant peroxidase activity that is capable of converting 2,4,6-trihalophenols to the corresponding 2,6-dihaloquinones in the presence of hydrogen peroxide. Here, a comprehensive structural study of recombinant DHP B, both by itself and cocrystallized with isoenzyme A, using X-ray diffraction is presented. The structure of DHP B refined to 1.58 {angstrom} resolution exhibits the same distal histidine (His55) conformational flexibility as that observed in isoenzyme A, as well as additional changes to the distal and proximal hydrogen-bonding networks. Furthermore, preliminary characterization of the DHP AB heterodimer is presented, which exhibits differences in the AB interface that are not observed in the A-only or B-only homodimers. These structural investigations of DHP B provide insights that may relate to the mechanistic details of the H{sub 2}O{sub 2}-dependent oxidative dehalogenation reaction catalyzed by dehaloperoxidase, present a clearer description of the function of specific residues in DHP at the molecular level and lead to a better understanding of the paradigms of globin structure-function relationships.
Research Organization:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Organization:
UNIVERSITYNIHU.S. ARMY RESEARCH
OSTI ID:
1033803
Journal Information:
Acta Crystallogr. D, Journal Name: Acta Crystallogr. D Journal Issue: (5) ; 05, 2010 Vol. 66; ISSN 0907-4449
Country of Publication:
United States
Language:
ENGLISH