Bindings of NO, CO, and O2 to multifunctional globin type dehaloperoxidase follow the ‘sliding scale rule’
- 5 October 2017
- journal article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 474 (20), 3485-3498
- https://doi.org/10.1042/bcj20170515
Abstract
Dehaloperoxidase–hemoglobin (DHP), a multifunctional globin protein, not only functions as an oxygen carrier as typical globins such as myoglobin and hemoglobin, but also as a peroxidase, a mono- and dioxygenase, peroxygenase, and an oxidase. Kinetics of DHP binding to NO, CO, and O2 were characterized for wild-type DHP A and B and the H55D and H55V DHP A mutants using stopped-flow methods. All three gaseous ligands bind to DHP significantly more weakly than sperm whale myoglobin (SWMb). Both CO and NO bind to DHP in a one-step process to form a stable six-coordinate complex. Multiple-step NO binding is not observed in DHP, which is similar to observations in SWMb, but in contrast with many heme sensor proteins. The weak affinity of DHP for O2 is mainly due to a fast O2 dissociation rate, in accordance with a longer εN–Fe distance between the heme iron and distal histidine in DHP than that in Mb, and an open-distal pocket that permits ligand escape. Binding affinities in DHP show the same 3–4 orders separation between the pairs NO/CO and CO/O2, consistent with the ‘sliding scale rule’ hypothesis. Strong gaseous ligand discrimination by DHP is very different from that observed in typical peroxidases, which show poor gaseous ligand selectivity, correlating with a neutral proximal imidazole ligand rather than an imidazolate. The present study provides useful insights into the rationale for DHP to function both as mono-oxygenase and oxidase, and is the first example of a globin peroxidase shown to follow the ‘sliding scale rule’ hypothesis in gaseous ligand discrimination.This publication has 46 references indexed in Scilit:
- The Role of the Distal Histidine in H2O2 Activation and Heme Protection in both Peroxidase and Globin FunctionsThe Journal of Physical Chemistry B, 2012
- A “Sliding Scale Rule” for Selectivity among NO, CO, and O2 by Heme Protein SensorsBiochemistry, 2011
- Reactivity of Deoxy- and Oxyferrous Dehaloperoxidase B from Amphitrite ornata: Identification of Compound II and Its Ferrous–Hydroperoxide PrecursorBiochemistry, 2011
- Kinetic Analysis of a Naturally Occurring Bioremediation Enzyme: Dehaloperoxidase-Hemoglobin from Amphitrite ornataThe Journal of Physical Chemistry B, 2010
- Is Nostoc H-NOX a NO Sensor or Redox Switch?Biochemistry, 2010
- Spectroscopic and Mechanistic Investigations of Dehaloperoxidase B fromAmphitrite ornataBiochemistry, 2010
- Prostaglandin H synthase: Resolved and unresolved mechanistic issuesArchives of Biochemistry and Biophysics, 2010
- Proximal Cavity, Distal Histidine, and Substrate Hydrogen-Bonding Mutations Modulate the Activity of Amphitrite ornata DehaloperoxidaseBiochemistry, 2006
- Amphitrite ornata, a Marine Worm, Contains Two Dehaloperoxidase GenesMarine Biotechnology, 2001
- How does NO activate hemeproteins?FEBS Letters, 1994