@article{serrano_davis_gaff_zhang_chen_d'antonio_bowden_rose_franzen_2010, title={X-ray structure of the metcyano form of dehaloperoxidase from Amphitrite ornata: Evidence for photoreductive dissociation of the iron-cyanide bond}, volume={66}, journal={Acta Crystallographica. Section D, Biological Crystallography}, author={Serrano, V. S. and Davis, M. F. and Gaff, J. F. and Zhang, Q. and Chen, Z. and D'Antonio, E. L. and Bowden, E. F. and Rose, R. and Franzen, S.}, year={2010}, pages={770–782} }
 @article{chen_serrano_betts_franzen_2009, title={Distal histidine conformational flexibility in dehaloperoxidase from Amphitrite ornata}, volume={65}, ISSN={["2059-7983"]}, DOI={10.1107/S0907444908036548}, abstractNote={The enzyme dehaloperoxidase (DHP) from the terebellid polychaete Amphitrite ornata is a heme protein which has a globin fold but can function as both a hemoglobin and a peroxidase. As a peroxidase, DHP is capable of converting 2,4,6-trihalophenols to the corresponding 2,6-dihaloquinones in the presence of hydrogen peroxide. As a hemoglobin, DHP cycles between the oxy and deoxy states as it reversibly binds oxygen for storage. Here, it is reported that the distal histidine, His55, exhibits conformational flexibility in the deoxy form and is consequently observed in two solvent-exposed conformations more than 9.5 A away from the heme. These conformations are analogous to the open conformation of sperm whale myoglobin. The heme iron in deoxy ferrous DHP is five-coordinate and has an out-of-plane displacement of 0.25 A from the heme plane. The observation of five-coordinate heme iron with His55 in a remote solvent-exposed conformation is consistent with the hypothesis that His55 interacts with heme iron ligands through hydrogen bonding in the closed conformation. Since His55 is also displaced by the binding of 4-iodophenol in an internal pocket, these results provide new insight into the correlation between heme iron ligation, molecular binding in the distal pocket and the conformation of the distal histidine in DHP.}, journal={ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY}, author={Chen, Zuxu and Serrano, Vesna and Betts, Laurie and Franzen, Stefan}, year={2009}, month={Jan}, pages={34–40} }
 @article{serrano_chen_davis_franzen_2007, title={X-ray crystal structural analysis of the binding site in the ferric and oxyferrous forms of the recombinant heme dehaloperoxidase cloned from Amphitrite ornata}, volume={63}, ISSN={["2059-7983"]}, DOI={10.1107/S0907444907043417}, abstractNote={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.}, journal={ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY}, author={Serrano, Vesna and Chen, Zuxu and Davis, Michael F. and Franzen, Stefan}, year={2007}, month={Oct}, pages={1094–1101} }