dc.contributor.author | Clarke, DJ | |
dc.contributor.author | Mackay, CL | |
dc.contributor.author | Campopiano, DJ | |
dc.contributor.author | Langridge-Smith, P | |
dc.contributor.author | Brown, Alan R | |
dc.date.accessioned | 2013-05-08T09:15:54Z | |
dc.date.issued | 2009-05-12 | |
dc.description.abstract | Bacterioferritin comigratory protein (BCP) is a bacterial thioredoxin-dependent thiol peroxidase that reduces a variety of peroxide substrates. Using high-resolution Fourier transform ion cyclotron resonance mass spectrometry coupled with top-down fragmentation techniques, we have analyzed the mechanistic details of hydrogen peroxide reduction by E. coli BCP. We show here that catalysis occurs via an atypical two-cysteine peroxiredoxin pathway. A transient sulfenic acid is initially formed on Cys-45, before resolution by the formation of an intramolecular disulfide bond between Cys-45 and Cys-50. This oxidized BCP intermediate is shown to be a substrate for reduction by thioredoxin, completing the catalytic cycle. Although we invoke Cys-50 in the catalytic cycle of Escherichia coli bacterioferritin comigratory protein (BCP), a previous study had shown that this residue was not absolutely required for peroxiredoxin activity. In order to explain these apparently conflicting phenomena, we analyzed the reaction of a C50S BCP mutant with peroxide. We show that this mutant BCP enzyme adopts a different and novel mechanistic pathway. The C50S BCP mutant reacts with peroxide to form a sulfenic acid on Cys-45, in the same manner as wild-type BCP. However, the nascent intermediate is then resolved by reaction with Cys-45 from a second BCP molecule, resulting in a dimeric intermediate containing an intermolecular disulfide bond. We further show that this novel resolving complex is a substrate for reduction by thioredoxin. The importance of our results in furthering the understanding of catalysis within BCP family is discussed. | en_GB |
dc.identifier.citation | Vol. 48, Issue 18, pp. 3904 - 3914 | en_GB |
dc.identifier.doi | 10.1021/bi900189e | |
dc.identifier.uri | http://hdl.handle.net/10871/9082 | |
dc.language.iso | en | en_GB |
dc.publisher | American Chemical Society | en_GB |
dc.relation.url | http://pubs.acs.org/doi/abs/10.1021/bi900189e | en_GB |
dc.subject | Amino Acid Sequence | en_GB |
dc.subject | Bacterial Proteins | en_GB |
dc.subject | Biocatalysis | en_GB |
dc.subject | Chromatography, Affinity | en_GB |
dc.subject | Cytochrome b Group | en_GB |
dc.subject | Escherichia coli | en_GB |
dc.subject | Escherichia coli Proteins | en_GB |
dc.subject | Ferritins | en_GB |
dc.subject | Molecular Sequence Data | en_GB |
dc.subject | Oxidation-Reduction | en_GB |
dc.subject | Recombinant Proteins | en_GB |
dc.subject | Spectroscopy, Fourier Transform Infrared | en_GB |
dc.subject | Tandem Mass Spectrometry | en_GB |
dc.subject | Thioredoxins | en_GB |
dc.title | Interrogating the molecular details of the peroxiredoxin activity of the Escherichia coli bacterioferritin comigratory protein using high-resolution mass spectrometry. | en_GB |
dc.type | Article | en_GB |
dc.date.available | 2013-05-08T09:15:54Z | |
dc.identifier.issn | 0006-2960 | |
exeter.place-of-publication | United States | |
dc.description | © American Chemical Society, 2009. Post-print version of article deposited in accordance with SHERPA RoMEO guidelines | en_GB |
dc.identifier.journal | Biochemistry | en_GB |