Gene Ontology annotation through association of InterPro records with GO terms

Annotation inferences using phylogenetic trees

Combined Automated Annotation using Multiple IEA Methods

Thioredoxin-dependent hydroperoxide peroxidase activity of bacterioferritin comigratory protein (BCP) as a new member of the thiol-specific antioxidant protein (TSA)/Alkyl hydroperoxide peroxidase C (AhpC) family.

BCP is a thioredoxin-dependent thiol peroxidase that reduces H2O2 and organic hydroperoxides. Cys-45 is the essential catalytic residue.

"BCP showed a thioredoxin-dependent thiol peroxidase activity...Replacement of Cys-45 with serine resulted in the complete loss of thiol peroxidase activity"
BCP preferentially reduces linoleic acid hydroperoxide over H2O2 and t-butyl hydroperoxide when using thioredoxin as electron donor.

"BCP preferentially reduced linoleic acid hydroperoxide rather than H(2)O(2) and t-butyl hydroperoxide with the use of thioredoxin as an in vivo immediate electron donor"
BCP exists as a monomer and its functional Cys-45 exists as cysteine sulfenic acid intermediate during catalysis.

"BCP exists as a monomer, and its functional Cys-45 appeared to exist as cysteine sulfenic acid"
BCP expression is induced by oxidative stress and the bcp null mutant is hypersensitive to oxidants.

"BCP was induced 3-fold by the oxidative stress given by changing the growth conditions from the anaerobic to aerobic culture. Bcp null mutant grew more slowly than its wild type in aerobic culture and showed the hypersensitivity toward various oxidants"

PMID:15911532

Localization, annotation, and comparison of the Escherichia coli K-12 proteome under two states of growth.

BCP was identified in the cytosolic fraction of E. coli K-12.

"a proteomic analysis of Escherichia coli in which 3,199 protein forms were detected, and of those 2,160 were annotated and assigned to the cytosol, periplasm, inner membrane, and outer membrane"

PMID:18304323

Protein abundance profiling of the Escherichia coli cytosol.

BCP was identified among 1103 proteins in the E. coli cytosolic fraction, independently confirming cytosolic localization.

"we identified 1103 proteins from the cytosolic fraction of the Escherichia coli strain MC4100"

PMID:21910476

Kinetic and thermodynamic features reveal that Escherichia coli BCP is an unusually versatile peroxiredoxin.

BCP is a monomer by analytical ultracentrifugation and has broad substrate specificity, using multiple reducing substrates (Trx1, Trx2, Grx1, Grx3).

"both oxidized and reduced E. coli BCP behave as monomers in solution...BCP can utilize a variety of reducing substrates, including Trx1, Trx2, Grx1, and Grx3"
BCP has the highest redox potential (-146 mV) of any characterized peroxiredoxin, suggesting it remains active under highly oxidizing conditions.

"BCP exhibited a high redox potential of -145.9 ± 3.2 mV, the highest to date observed for a Prx"
BCP shows broad peroxide specificity with comparable rates for H2O2 and cumene hydroperoxide, and a pKa of ~5.8 for the peroxidatic Cys45.

"BCP exhibited a broad peroxide specificity, with comparable rates for H(2)O(2) and cumene hydroperoxide...a pK(a) of ~5.8 for the peroxidatic cysteine (Cys45)"

PMID:19298085

Interrogating the molecular details of the peroxiredoxin activity of the Escherichia coli bacterioferritin comigratory protein using high-resolution mass spectrometry.

BCP is an atypical 2-Cys peroxiredoxin that forms an intramolecular disulfide between Cys-45 and Cys-50 during catalysis.

"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"
The C50S mutant adopts an alternative mechanism forming an intermolecular disulfide between two BCP molecules.

"The C50S BCP mutant reacts with peroxide to form a sulfenic acid on Cys-45... resulting in a dimeric intermediate containing an intermolecular disulfide bond"

PMID:20078128

Subdivision of the bacterioferritin comigratory protein family of bacterial peroxiredoxins based on catalytic activity.

The BCP family is subdivided into atypical 2-Cys (like E. coli BCP) and 1-Cys classes based on catalytic mechanism.

"These studies support the subdivision of the BCP family of peroxiredoxins into two classes based on their catalytic activity"

file:ECOLI/bcp/bcp-deep-research-bioreason-sft.md

BioReason-Pro SFT deep research for bcp

Domain architecture analysis correctly identifies the thioredoxin-like scaffold harboring peroxiredoxin-specific catalytic signatures, supporting thiol-based peroxidase function.

file:ECOLI/bcp/bcp-deep-research-falcon.md

Falcon (Edison Scientific) deep research report for E. coli bcp (P0AE52): Peroxiredoxin Bcp/PrxQ functional annotation

BCP is an atypical 2-Cys peroxiredoxin with a CPXXXXCR active-site motif; Cys45 is the peroxidatic cysteine and Cys50 the resolving cysteine.

"Cys45 is the peroxidatic cysteine (Cp) and Cys50 is the resolving cysteine (Cr); Cys99 is present but not the primary catalytic thiol. C45S abolishes detectable Trx-dependent peroxidase/antioxidant activity."
Later kinetic work established broad peroxide substrate specificity for BCP, supporting its description as an unusually versatile peroxiredoxin.

"later kinetic work showed broad peroxide specificity, with comparable rates for H2O2 and cumene hydroperoxide under some assay conditions"
BCP has relaxed reductant specificity, accepting electrons from thioredoxins (Trx1, Trx2) and glutaredoxins (Grx1, Grx3).

"Bcp can also use Trx2 and glutaredoxins Grx1 and Grx3 as alternative reducing partners, indicating relaxed reductant specificity."
BCP is monomeric in solution up to at least 200 uM, consistent with the monomeric oligomeric-state annotation.

"BCP is reported as **monomeric** in solution up to at least **200 µM**"
BCP has an unusually high midpoint redox potential, supporting activity under relatively oxidizing intracellular conditions.

"relatively **high midpoint potential** for BCP of **−145.9 ± 3.2 mV**"
The peroxidatic Cys45 has a low pKa (~5.8), consistent with a reactive thiolate at physiological pH.

"Peroxidatic Cys45 **pKa ~5.8**, consistent with a reactive thiolate at physiological pH."
A bcp promoter-lacZ fusion showed oxygen-responsive expression, with an approximately 3-fold increase in activity under oxygen stress.

"approximately **3-fold increase** in β-galactosidase activity under oxygen stress"
Cytosolic localization of E. coli BCP is the best-supported annotation but remains an inference; no direct localization experiment was found in the retrieved literature.

"best-supported annotation is cytosolic localization, but this remains inference rather than direct localization evidence"