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Protein

Protoporphyrinogen oxidase, chloroplastic/mitochondrial

Gene

POX2

Organism
Spinacia oleracea (Spinach)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Catalyzes the 6-electron oxidation of protoporphyrinogen-IX to form protoporphyrin-IX.1 Publication
Provides precursor for the mitochondrial and plastidic heme synthesis and the predominant chlorophyll synthesis in plastids.1 Publication

Catalytic activityi

Protoporphyrinogen-IX + 3 O2 = protoporphyrin-IX + 3 H2O2.

Cofactori

FADBy similarityNote: Binds 1 FAD per subunit.By similarity

Pathway:iprotoporphyrin-IX biosynthesis

This protein is involved in step 1 of the subpathway that synthesizes protoporphyrin-IX from protoporphyrinogen-IX.
Proteins known to be involved in this subpathway in this organism are:
  1. Protoporphyrinogen oxidase, chloroplastic/mitochondrial (POX2)
This subpathway is part of the pathway protoporphyrin-IX biosynthesis, which is itself part of Porphyrin-containing compound metabolism.
View all proteins of this organism that are known to be involved in the subpathway that synthesizes protoporphyrin-IX from protoporphyrinogen-IX, the pathway protoporphyrin-IX biosynthesis and in Porphyrin-containing compound metabolism.

Pathway:ichlorophyll biosynthesis

This protein is involved in the pathway chlorophyll biosynthesis, which is part of Porphyrin-containing compound metabolism.
View all proteins of this organism that are known to be involved in the pathway chlorophyll biosynthesis and in Porphyrin-containing compound metabolism.

Sites

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Binding sitei294 – 2941FAD; via amide nitrogen and carbonyl oxygenBy similarity

Regions

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Nucleotide bindingi49 – 546FADBy similarity
Nucleotide bindingi72 – 732FADBy similarity
Nucleotide bindingi94 – 974FADBy similarity
Nucleotide bindingi501 – 5033FADBy similarity

GO - Molecular functioni

  • oxygen-dependent protoporphyrinogen oxidase activity Source: UniProtKB

GO - Biological processi

  • chlorophyll biosynthetic process Source: UniProtKB
  • heme biosynthetic process Source: UniProtKB
  • protoporphyrinogen IX biosynthetic process Source: UniProtKB-UniPathway
Complete GO annotation...

Keywords - Molecular functioni

Oxidoreductase

Keywords - Biological processi

Chlorophyll biosynthesis, Heme biosynthesis, Porphyrin biosynthesis

Keywords - Ligandi

FAD, Flavoprotein

Enzyme and pathway databases

UniPathwayiUPA00251; UER00324.
UPA00668.

Names & Taxonomyi

Protein namesi
Recommended name:
Protoporphyrinogen oxidase, chloroplastic/mitochondrial (EC:1.3.3.4)
Short name:
Protox II
Alternative name(s):
SO-POX2
Gene namesi
Name:POX2
OrganismiSpinacia oleracea (Spinach)
Taxonomic identifieri3562 [NCBI]
Taxonomic lineageiEukaryotaViridiplantaeStreptophytaEmbryophytaTracheophytaSpermatophytaMagnoliophytaeudicotyledonsGunneridaePentapetalaeCaryophyllalesAmaranthaceaeChenopodioideaeAnserineaeSpinacia

Subcellular locationi

GO - Cellular componenti

  • chloroplast inner membrane Source: UniProtKB
  • mitochondrial inner membrane Source: UniProtKB
Complete GO annotation...

Keywords - Cellular componenti

Chloroplast, Membrane, Mitochondrion, Mitochondrion inner membrane, Plastid, Plastid inner membrane

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Mutagenesisi27 – 271M → I: Directs expression to chloroplasts only, due to lack of alternative translation. 1 Publication

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Transit peptidei1 – 4848ChloroplastSequence AnalysisAdd
BLAST
Transit peptidei27 – 4822MitochondrionSequence AnalysisAdd
BLAST
Chaini49 – 531483Protoporphyrinogen oxidase, chloroplastic/mitochondrialPRO_0000013327Add
BLAST

Interactioni

Subunit structurei

Homodimer.By similarity

Structurei

3D structure databases

ProteinModelPortaliQ94IG7.
SMRiQ94IG7. Positions 42-523.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Belongs to the protoporphyrinogen oxidase family.Curated

Keywords - Domaini

Transit peptide

Family and domain databases

Gene3Di3.90.660.20. 1 hit.
InterProiIPR002937. Amino_oxidase.
IPR027418. PPOX_C.
IPR004572. Protoporphyrinogen_oxidase.
[Graphical view]
PfamiPF01593. Amino_oxidase. 1 hit.
[Graphical view]
TIGRFAMsiTIGR00562. proto_IX_ox. 1 hit.

Sequences (2)i

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

This entry describes 2 isoformsi produced by alternative initiation. AlignAdd to basket

Isoform L (identifier: Q94IG7-1) [UniParc]FASTAAdd to basket

Also known as: Protox IIL

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MVILPVSQLS TNLGLSLVSP TKNNPVMGNV SERNQVNQPI SAKRVAVVGA
60 70 80 90 100
GVSGLAAAYK LKSNGLNVTL FEADSRAGGK LKTVVKDGLI WDEGANTMTE
110 120 130 140 150
SDEEVTSLFD DLGIREKLQL PISQNKRYIA RDGLPVLLPS NPVALLKSNI
160 170 180 190 200
LSAKSKLQIM LEPFLWKKHN GAKVSDENAQ ESVAEFFERH FGKEFVDYLI
210 220 230 240 250
DPFVAGTSGG DPQSLSMRHA FPELWNIENR FGSVISGFIQ SKLSSKKEKG
260 270 280 290 300
GEKQSSNKKP RVRGSFSFQG GMQTLVDTIC KEFGEDELKL QSEVLSLSYS
310 320 330 340 350
HNGSLTSENW SVSSMSNSTI QDQPYDAVVV TAPINNVKEL KIMKVENPFS
360 370 380 390 400
LDFIPEVSCL PLSVIITTFK KTNVKRPLEG FGVLVPSNEQ HNGLKTLGTL
410 420 430 440 450
FSSMMFPDRA PSDVYLYTTF VGGSRNRELA KASTDELKQI VSSDLQQLLG
460 470 480 490 500
TEGEPTFVNH FYWSKAFPLY GRNYDSVLRA IEKMERDLPG LFYAGNHKGG
510 520 530
LSVGKSIASG YKAAELAISY LESNKMTEET I
Length:531
Mass (Da):58,320
Last modified:December 1, 2001 - v1
Checksum:i4D4F900EDCB36C12
GO
Isoform S (identifier: Q94IG7-2) [UniParc]FASTAAdd to basket

Also known as: Protox IIS

The sequence of this isoform differs from the canonical sequence as follows:
     1-26: Missing.

Show »
Length:505
Mass (Da):55,616
Checksum:i578D0238FB7B2B78
GO

Alternative sequence

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Alternative sequencei1 – 2626Missing in isoform S. 1 PublicationVSP_018805Add
BLAST

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AB046993 mRNA. Translation: BAB60710.1.

Keywords - Coding sequence diversityi

Alternative initiation

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AB046993 mRNA. Translation: BAB60710.1.

3D structure databases

ProteinModelPortaliQ94IG7.
SMRiQ94IG7. Positions 42-523.
ModBaseiSearch...
MobiDBiSearch...

Chemistry

ChEMBLiCHEMBL2366509.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Enzyme and pathway databases

UniPathwayiUPA00251; UER00324.
UPA00668.

Family and domain databases

Gene3Di3.90.660.20. 1 hit.
InterProiIPR002937. Amino_oxidase.
IPR027418. PPOX_C.
IPR004572. Protoporphyrinogen_oxidase.
[Graphical view]
PfamiPF01593. Amino_oxidase. 1 hit.
[Graphical view]
TIGRFAMsiTIGR00562. proto_IX_ox. 1 hit.
ProtoNetiSearch...

Publicationsi

  1. "Dual targeting of spinach protoporphyrinogen oxidase II to mitochondria and chloroplasts by alternative use of two in-frame initiation codons."
    Watanabe N., Che F.-S., Iwano M., Takayama S., Yoshida S., Isogai A.
    J. Biol. Chem. 276:20474-20481(2001) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS L AND S), FUNCTION, SUBCELLULAR LOCATION, MUTAGENESIS OF MET-27.
    Tissue: Leaf.

Entry informationi

Entry nameiPPOCM_SPIOL
AccessioniPrimary (citable) accession number: Q94IG7
Entry historyi
Integrated into UniProtKB/Swiss-Prot: January 4, 2005
Last sequence update: December 1, 2001
Last modified: November 26, 2014
This is version 58 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programPlant Protein Annotation Program

Miscellaneousi

Documents

  1. PATHWAY comments
    Index of metabolic and biosynthesis pathways
  2. SIMILARITY comments
    Index of protein domains and families

External Data

Dasty 3

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 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.