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Protein

Cytochrome bd-II ubiquinol oxidase subunit 2

Gene

appB

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: -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

Caution

Was originally thought not to translocate protons.1 Publication

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 transfer 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

Keywordsi

Molecular functionOxidoreductase
Biological processElectron transport, Transport
LigandHeme, Iron, Metal-binding

Enzyme and pathway databases

BioCyciEcoCyc:APPB-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 lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG11379 appB

Subcellular locationi

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini1 – 8CytoplasmicSequence analysis8
Transmembranei9 – 28HelicalSequence analysisAdd BLAST20
Topological domaini29 – 79PeriplasmicSequence analysisAdd BLAST51
Transmembranei80 – 99HelicalSequence analysisAdd BLAST20
Topological domaini100 – 122CytoplasmicSequence analysisAdd BLAST23
Transmembranei123 – 142HelicalSequence analysisAdd BLAST20
Topological domaini143 – 164PeriplasmicSequence analysisAdd BLAST22
Transmembranei165 – 184HelicalSequence analysisAdd BLAST20
Topological domaini185 – 205CytoplasmicSequence analysisAdd BLAST21
Transmembranei206 – 225HelicalSequence analysisAdd BLAST20
Topological domaini226 – 261PeriplasmicSequence analysisAdd BLAST36
Transmembranei262 – 281HelicalSequence analysisAdd BLAST20
Topological domaini282 – 291CytoplasmicSequence analysis10
Transmembranei292 – 311HelicalSequence analysisAdd BLAST20
Topological domaini312 – 335PeriplasmicSequence analysisAdd BLAST24
Transmembranei336 – 355HelicalSequence analysisAdd BLAST20
Topological domaini356 – 378CytoplasmicSequence analysisAdd BLAST23

GO - Cellular componenti

  • cytochrome complex Source: EcoCyc
  • integral component of membrane Source: UniProtKB-KW
  • plasma membrane Source: EcoCyc

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)DescriptionActionsGraphical viewLength
ChainiPRO_00001839281 – 378Cytochrome bd-II ubiquinol oxidase subunit 2Add BLAST378

Proteomic databases

PaxDbiP26458
PRIDEiP26458

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, 138 interactors
IntActiP26458, 1 interactor
STRINGi316385.ECDH10B_1049

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
OMAiTAWAYWV
PhylomeDBiP26458

Family and domain databases

InterProiView protein in InterPro
IPR003317 Cyt-d_oxidase_su2
PANTHERiPTHR43141 PTHR43141, 1 hit
PfamiView protein in Pfam
PF02322 Cyt_bd_oxida_II, 1 hit
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)DescriptionActionsGraphical viewLength
Sequence conflicti297M → I in AAB20285 (PubMed:1658595).Curated1

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
PATRICifig|511145.12.peg.1013

Similar proteinsi

Entry informationi

Entry nameiAPPB_ECOLI
AccessioniPrimary (citable) accession number: P26458
Secondary accession number(s): P77278
Entry historyiIntegrated into UniProtKB/Swiss-Prot: August 1, 1992
Last sequence update: November 1, 1997
Last modified: March 28, 2018
This is version 137 of the entry and version 2 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

Complete proteome, Reference proteome
UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health