Open AccessStructure of dehaloperoxidase B at 1.58 Å resolution and structural characterization of the AB dimer from Amphitrite ornata
Author(s) -
De Serrano Vesna,
D'Antonio Jennifer,
Franzen Stefan,
Ghiladi Reza A.
Publication year - 2010
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s0907444910004580
Subject(s) - dimer , stereochemistry , isozyme , chemistry , globin , histidine , resolution (logic) , crystallography , hemoglobin , biochemistry , enzyme , organic chemistry , artificial intelligence , computer science
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 Å 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 2 O 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.