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Protein

Cytochrome bd-II ubiquinol oxidase subunit 2

Gene

appB

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

A terminal oxidase that catalyzes quinol-dependent, Na+-independent oxygen uptake. Prefers menadiol over other quinols although ubiquinol was not tested (PubMed:8626304). Generates a proton motive force using protons and electrons from opposite sides of the membrane to generate H2O, transferring 1 proton/electron.4 Publications

Catalytic activityi

2 ubiquinol + O2 + n H+(Side 1) = 2 ubiquinone + 2 H2O + n H+(Side 2).

Cofactori

hemeCuratedNote: May bind up to 3 heme groups per complex.Curated

Enzyme regulationi

Inhibited by cyanide; is more sensitive to cyanide than cytochrome bd-I oxidase.1 Publication

Pathwayi: oxidative phosphorylation

This protein is involved in the pathway oxidative phosphorylation, which is part of Energy metabolism.
View all proteins of this organism that are known to be involved in the pathway oxidative phosphorylation and in Energy metabolism.

GO - Molecular functioni

  • electron carrier activity Source: EcoCyc
  • metal ion binding Source: UniProtKB-KW
  • oxidoreductase activity, acting on diphenols and related substances as donors, oxygen as acceptor Source: EcoCyc

GO - Biological processi

  • aerobic electron transport chain Source: EcoCyc
  • oxidative phosphorylation Source: UniProtKB-UniPathway
Complete GO annotation...

Keywords - Molecular functioni

Oxidoreductase

Keywords - Biological processi

Electron transport, Transport

Keywords - Ligandi

Heme, Iron, Metal-binding

Enzyme and pathway databases

BioCyciEcoCyc:APPB-MONOMER.
ECOL316407:JW0961-MONOMER.
MetaCyc:APPB-MONOMER.
BRENDAi1.10.3.14. 2026.
UniPathwayiUPA00705.

Names & Taxonomyi

Protein namesi
Recommended name:
Cytochrome bd-II ubiquinol oxidase subunit 2 (EC:1.10.3.10)
Alternative name(s):
Cytochrome bd-II oxidase subunit II
Gene namesi
Name:appB
Synonyms:cbdB, cyxB
Ordered Locus Names:b0979, JW0961
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacterialesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG11379. appB.

Subcellular locationi

Topology

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Topological domaini1 – 88CytoplasmicSequence analysis
Transmembranei9 – 2820HelicalSequence analysisAdd
BLAST
Topological domaini29 – 7951PeriplasmicSequence analysisAdd
BLAST
Transmembranei80 – 9920HelicalSequence analysisAdd
BLAST
Topological domaini100 – 12223CytoplasmicSequence analysisAdd
BLAST
Transmembranei123 – 14220HelicalSequence analysisAdd
BLAST
Topological domaini143 – 16422PeriplasmicSequence analysisAdd
BLAST
Transmembranei165 – 18420HelicalSequence analysisAdd
BLAST
Topological domaini185 – 20521CytoplasmicSequence analysisAdd
BLAST
Transmembranei206 – 22520HelicalSequence analysisAdd
BLAST
Topological domaini226 – 26136PeriplasmicSequence analysisAdd
BLAST
Transmembranei262 – 28120HelicalSequence analysisAdd
BLAST
Topological domaini282 – 29110CytoplasmicSequence analysis
Transmembranei292 – 31120HelicalSequence analysisAdd
BLAST
Topological domaini312 – 33524PeriplasmicSequence analysisAdd
BLAST
Transmembranei336 – 35520HelicalSequence analysisAdd
BLAST
Topological domaini356 – 37823CytoplasmicSequence analysisAdd
BLAST

GO - Cellular componenti

  • cytochrome complex Source: EcoCyc
  • integral component of membrane Source: UniProtKB-KW
  • plasma membrane Source: EcoCyc
Complete GO annotation...

Keywords - Cellular componenti

Cell inner membrane, Cell membrane, Membrane

Pathology & Biotechi

Disruption phenotypei

3-fold decreased ubiquinone levels but no change in redox levels of the ubiquinone pool (in aerobically grown minimal medium with glucose).3 Publications

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 378378Cytochrome bd-II ubiquinol oxidase subunit 2PRO_0000183928Add
BLAST

Proteomic databases

PaxDbiP26458.

Expressioni

Inductioni

Induced when bacterial cultures reach stationary phase; synthesis is triggered by phosphate starvation or a shift from aerobic to anaerobic conditions.1 Publication

Interactioni

Subunit structurei

Heterodimer of subunits I and II.1 Publication

Protein-protein interaction databases

BioGridi4260034. 136 interactions.
IntActiP26458. 1 interaction.
STRINGi511145.b0979.

Structurei

3D structure databases

ProteinModelPortaliP26458.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiENOG4105CFY. Bacteria.
COG1294. LUCA.
HOGENOMiHOG000084824.
InParanoidiP26458.
KOiK00426.
OMAiSTLEIVW.
OrthoDBiEOG6K4031.
PhylomeDBiP26458.

Family and domain databases

InterProiIPR003317. Cyt-d_oxidase_su2.
[Graphical view]
PfamiPF02322. Cyt_bd_oxida_II. 1 hit.
[Graphical view]
PIRSFiPIRSF000267. Cyt_oxidse_sub2. 1 hit.
TIGRFAMsiTIGR00203. cydB. 1 hit.

Sequencei

Sequence statusi: Complete.

P26458-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MFDYETLRFI WWLLIGVILV VFMISDGFDM GIGCLLPLVA RNDDERRIVI
60 70 80 90 100
NSVGAHWEGN QVWLILAGGA LFAAWPRVYA AAFSGFYVAM ILVLCSLFFR
110 120 130 140 150
PLAFDYRGKI ADARWRKMWD AGLVIGSLVP PVVFGIAFGN LLLGVPFAFT
160 170 180 190 200
PQLRVEYLGS FWQLLTPFPL LCGLLSLGMV ILQGGVWLQL KTVGVIHLRS
210 220 230 240 250
QLATKRAALL VMLCFLLAGY WLWVGIDGFV LLAQDANGPS NPLMKLVAVL
260 270 280 290 300
PGAWMNNFVE SPVLWIFPLL GFFCPLLTVM AIYRGRPGWG FLMASLMQFG
310 320 330 340 350
VIFTAGITLF PFVMPSSVSP ISSLTLWDST SSQLTLSIML VIVLIFLPIV
360 370
LLYTLWSYYK MWGRMTTETL RRNENELY
Length:378
Mass (Da):42,424
Last modified:November 1, 1997 - v2
Checksum:i8184B10C47660002
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti297 – 2971M → I in AAB20285 (PubMed:1658595).Curated

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
S63811 Genomic DNA. Translation: AAB20285.1.
U00096 Genomic DNA. Translation: AAC74064.1.
AP009048 Genomic DNA. Translation: BAA35744.1.
RefSeqiNP_415498.1. NC_000913.3.
WP_000460803.1. NZ_LN832404.1.

Genome annotation databases

EnsemblBacteriaiAAC74064; AAC74064; b0979.
BAA35744; BAA35744; BAA35744.
GeneIDi947547.
KEGGiecj:JW0961.
eco:b0979.
PATRICi32117179. VBIEscCol129921_1013.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
S63811 Genomic DNA. Translation: AAB20285.1.
U00096 Genomic DNA. Translation: AAC74064.1.
AP009048 Genomic DNA. Translation: BAA35744.1.
RefSeqiNP_415498.1. NC_000913.3.
WP_000460803.1. NZ_LN832404.1.

3D structure databases

ProteinModelPortaliP26458.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi4260034. 136 interactions.
IntActiP26458. 1 interaction.
STRINGi511145.b0979.

Proteomic databases

PaxDbiP26458.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaiAAC74064; AAC74064; b0979.
BAA35744; BAA35744; BAA35744.
GeneIDi947547.
KEGGiecj:JW0961.
eco:b0979.
PATRICi32117179. VBIEscCol129921_1013.

Organism-specific databases

EchoBASEiEB1353.
EcoGeneiEG11379. appB.

Phylogenomic databases

eggNOGiENOG4105CFY. Bacteria.
COG1294. LUCA.
HOGENOMiHOG000084824.
InParanoidiP26458.
KOiK00426.
OMAiSTLEIVW.
OrthoDBiEOG6K4031.
PhylomeDBiP26458.

Enzyme and pathway databases

UniPathwayiUPA00705.
BioCyciEcoCyc:APPB-MONOMER.
ECOL316407:JW0961-MONOMER.
MetaCyc:APPB-MONOMER.
BRENDAi1.10.3.14. 2026.

Miscellaneous databases

PROiP26458.

Family and domain databases

InterProiIPR003317. Cyt-d_oxidase_su2.
[Graphical view]
PfamiPF02322. Cyt_bd_oxida_II. 1 hit.
[Graphical view]
PIRSFiPIRSF000267. Cyt_oxidse_sub2. 1 hit.
TIGRFAMsiTIGR00203. cydB. 1 hit.
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "A new oxygen-regulated operon in Escherichia coli comprises the genes for a putative third cytochrome oxidase and for pH 2.5 acid phosphatase (appA)."
    Dassa J., Fsihi H., Marck C., Dion M., Kieffer-Bontemps M., Boquet P.L.
    Mol. Gen. Genet. 229:341-352(1991) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], INDUCTION.
    Strain: K12.
  2. Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
    Strain: K12 / W3110 / ATCC 27325 / DSM 5911.
  3. Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
    Strain: K12 / MG1655 / ATCC 47076.
  4. "Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110."
    Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S., Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T.
    Mol. Syst. Biol. 2:E1-E5(2006) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
    Strain: K12 / W3110 / ATCC 27325 / DSM 5911.
  5. "Purification of a cytochrome bd terminal oxidase encoded by the Escherichia coli app locus from a delta cyo delta cyd strain complemented by genes from Bacillus firmus OF4."
    Sturr M.G., Krulwich T.A., Hicks D.B.
    J. Bacteriol. 178:1742-1749(1996) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION AS AN OXIDASE, ENZYME REGULATION, SUBUNIT.
  6. "Global topology analysis of the Escherichia coli inner membrane proteome."
    Daley D.O., Rapp M., Granseth E., Melen K., Drew D., von Heijne G.
    Science 308:1321-1323(2005) [PubMed] [Europe PMC] [Abstract]
    Cited for: SUBCELLULAR LOCATION, TOPOLOGY [LARGE SCALE ANALYSIS].
    Strain: K12 / MG1655 / ATCC 47076.
  7. "Respiration of Escherichia coli can be fully uncoupled via the nonelectrogenic terminal cytochrome bd-II oxidase."
    Bekker M., de Vries S., Ter Beek A., Hellingwerf K.J., de Mattos M.J.
    J. Bacteriol. 191:5510-5517(2009) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION AS AN OXIDASE, DISRUPTION PHENOTYPE.
    Strain: K12.
  8. "Aerobic respiratory chain of Escherichia coli is not allowed to work in fully uncoupled mode."
    Borisov V.B., Murali R., Verkhovskaya M.L., Bloch D.A., Han H., Gennis R.B., Verkhovsky M.I.
    Proc. Natl. Acad. Sci. U.S.A. 108:17320-17324(2011) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION AS AN OXIDASE, FUNCTION IN PROTON TRANSLOCATION, DISRUPTION PHENOTYPE.
    Strain: K12.
  9. "Uncoupling of substrate-level phosphorylation in Escherichia coli during glucose-limited growth."
    Sharma P., Hellingwerf K.J., de Mattos M.J., Bekker M.
    Appl. Environ. Microbiol. 78:6908-6913(2012) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION AS AN OXIDASE, FUNCTION IN PROTON TRANSLOCATION, DISRUPTION PHENOTYPE.
    Strain: K12.
  10. Cited for: REVIEW.

Entry informationi

Entry nameiAPPB_ECOLI
AccessioniPrimary (citable) accession number: P26458
Secondary accession number(s): P77278
Entry historyi
Integrated into UniProtKB/Swiss-Prot: August 1, 1992
Last sequence update: November 1, 1997
Last modified: January 20, 2016
This is version 127 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Caution

Was originally thought not to translocate protons.1 Publication

Keywords - Technical termi

Complete proteome, Reference proteome

Documents

  1. Escherichia coli
    Escherichia coli (strain K12): entries and cross-references to EcoGene
  2. PATHWAY comments
    Index of metabolic and biosynthesis pathways
  3. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.