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Protein

Oxygen-independent coproporphyrinogen III oxidase

Gene

hemN

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

Functioni

Involved in the heme biosynthesis. Catalyzes the anaerobic oxidative decarboxylation of propionate groups of rings A and B of coproporphyrinogen III to yield the vinyl groups in protoporphyrinogen IX. It can use NAD or NADP, but NAD is preferred.2 Publications

Miscellaneous

The structure carries two S-adenosyl-L-methionine binding sites with only one binding to iron-cluster.1 Publication

Catalytic activityi

Coproporphyrinogen III + 2 S-adenosyl-L-methionine = protoporphyrinogen IX + 2 CO2 + 2 L-methionine + 2 5'-deoxyadenosine.1 Publication

Cofactori

[4Fe-4S] cluster2 PublicationsNote: Binds 1 [4Fe-4S] cluster. The cluster is coordinated with 3 cysteines and an exchangeable S-adenosyl-L-methionine.2 Publications

Activity regulationi

Inhibited by EDTA.1 Publication

Pathwayi: protoporphyrin-IX biosynthesis

This protein is involved in step 1 of the subpathway that synthesizes protoporphyrinogen-IX from coproporphyrinogen-III (AdoMet route).
Proteins known to be involved in this subpathway in this organism are:
  1. Oxygen-independent coproporphyrinogen III oxidase (hemN)
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 protoporphyrinogen-IX from coproporphyrinogen-III (AdoMet route), the pathway protoporphyrin-IX biosynthesis and in Porphyrin-containing compound metabolism.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Binding sitei56S-adenosyl-L-methionine 11 Publication1
Metal bindingi62Iron-sulfur (4Fe-4S-S-AdoMet)1
Metal bindingi66Iron-sulfur (4Fe-4S-S-AdoMet)1
Binding sitei68S-adenosyl-L-methionine 2; via carbonyl oxygen1 Publication1
Metal bindingi69Iron-sulfur (4Fe-4S-S-AdoMet)1
Binding sitei112S-adenosyl-L-methionine 1; via amide nitrogen and carbonyl oxygen1 Publication1
Binding sitei145S-adenosyl-L-methionine 11 Publication1
Binding sitei172S-adenosyl-L-methionine 21 Publication1
Binding sitei184S-adenosyl-L-methionine 21 Publication1
Binding sitei209S-adenosyl-L-methionine 21 Publication1

GO - Molecular functioni

GO - Biological processi

Keywordsi

Molecular functionOxidoreductase
Biological processPorphyrin biosynthesis
Ligand4Fe-4S, Iron, Iron-sulfur, Metal-binding, S-adenosyl-L-methionine

Enzyme and pathway databases

BioCyciEcoCyc:HEMN-MONOMER
MetaCyc:HEMN-MONOMER
BRENDAi1.3.99.22 2026
UniPathwayi
UPA00251;UER00323

Names & Taxonomyi

Protein namesi
Recommended name:
Oxygen-independent coproporphyrinogen III oxidase (EC:1.3.98.31 Publication)
Short name:
CPO
Alternative name(s):
Coproporphyrinogen III dehydrogenase
Short name:
CPDH
Gene namesi
Name:hemN
Synonyms:yihJ
Ordered Locus Names:b3867, JW3838
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG11836 hemN

Subcellular locationi

GO - Cellular componenti

Keywords - Cellular componenti

Cytoplasm

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi56Y → A or L: Loss of activity. 2 Publications1
Mutagenesisi56Y → F: Decreases activity by 50%. 2 Publications1
Mutagenesisi58H → L: Results in loss of iron-sulfur cluster and activity. 1 Publication1
Mutagenesisi62C → S: Results in loss of iron-sulfur cluster and activity. 1 Publication1
Mutagenesisi66C → S: Results in loss of iron-sulfur cluster and activity. 1 Publication1
Mutagenesisi68F → L: No effect. 1 Publication1
Mutagenesisi69C → S: Results in loss of iron-sulfur cluster and activity. 1 Publication1
Mutagenesisi71C → S: No effect on iron-sulfur cluster, but results in activity loss. 1 Publication1
Mutagenesisi111G → V: Loss of activity and much less iron-sulfur cluster formed; when associated with V-113. 1 Publication1
Mutagenesisi113G → V: Loss of activity and much less iron-sulfur cluster formed; when associated with V-111. 1 Publication1
Mutagenesisi145E → A or I: Loss of activity. Iron content reduced by about 80%. 1 Publication1
Mutagenesisi310F → A or L: Loss of activity. Iron content reduced by about 50%. Can cleave up to one molecule of S-adenosyl-L-methionine (in vitro). 1 Publication1
Mutagenesisi311Q → A: Loss of activity. No change in iron content. Can cleave up to one molecule of S-adenosyl-L-methionine (in vitro). 1 Publication1
Mutagenesisi329I → A: Loss of activity. No change in iron content. Can cleave up to one molecule of S-adenosyl-L-methionine (in vitro). 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00001099411 – 457Oxygen-independent coproporphyrinogen III oxidaseAdd BLAST457

Proteomic databases

PaxDbiP32131
PRIDEiP32131

Interactioni

Subunit structurei

Monomer.2 Publications

Protein-protein interaction databases

BioGridi4262627, 13 interactors
DIPiDIP-9887N
IntActiP32131, 7 interactors
STRINGi316385.ECDH10B_4057

Structurei

Secondary structure

1457
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details

3D structure databases

ProteinModelPortaliP32131
SMRiP32131
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP32131

Family & Domainsi

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni113 – 114S-adenosyl-L-methionine 2 binding2

Sequence similaritiesi

Phylogenomic databases

eggNOGiENOG4105D4P Bacteria
COG0635 LUCA
HOGENOMiHOG000257214
InParanoidiP32131
KOiK02495
PhylomeDBiP32131

Family and domain databases

Gene3Di3.80.30.20, 1 hit
InterProiView protein in InterPro
IPR004558 Coprogen_oxidase_HemN
IPR034505 Coproporphyrinogen-III_oxidase
IPR006638 Elp3/MiaB/NifB
IPR010723 HemN_C
IPR007197 rSAM
IPR023404 rSAM_horseshoe
PANTHERiPTHR13932 PTHR13932, 1 hit
PfamiView protein in Pfam
PF06969 HemN_C, 1 hit
PF04055 Radical_SAM, 1 hit
PIRSFiPIRSF000167 HemN, 1 hit
SFLDiSFLDF00277 oxygen-independent_coproporphy, 1 hit
SFLDG01065 anaerobic_coproporphyrinogen-I, 1 hit
SFLDS00029 Radical_SAM, 2 hits
SMARTiView protein in SMART
SM00729 Elp3, 1 hit
TIGRFAMsiTIGR00538 hemN, 1 hit

Sequencei

Sequence statusi: Complete.

P32131-1 [UniParc]FASTAAdd to basket
« Hide
        10         20         30         40         50
MSVQQIDWDL ALIQKYNYSG PRYTSYPTAL EFSEDFGEQA FLQAVARYPE
60 70 80 90 100
RPLSLYVHIP FCHKLCYFCG CNKIVTRQQH KADQYLDALE QEIVHRAPLF
110 120 130 140 150
AGRHVSQLHW GGGTPTYLNK AQISRLMKLL RENFQFNADA EISIEVDPRE
160 170 180 190 200
IELDVLDHLR AEGFNRLSMG VQDFNKEVQR LVNREQDEEF IFALLNHARE
210 220 230 240 250
IGFTSTNIDL IYGLPKQTPE SFAFTLKRVA ELNPDRLSVF NYAHLPTIFA
260 270 280 290 300
AQRKIKDADL PSPQQKLDIL QETIAFLTQS GYQFIGMDHF ARPDDELAVA
310 320 330 340 350
QREGVLHRNF QGYTTQGDTD LLGMGVSAIS MIGDCYAQNQ KELKQYYQQV
360 370 380 390 400
DEQGNALWRG IALTRDDCIR RDVIKSLICN FRLDYAPIEK QWDLHFADYF
410 420 430 440 450
AEDLKLLAPL AKDGLVDVDE KGIQVTAKGR LLIRNICMCF DTYLRQKARM

QQFSRVI
Length:457
Mass (Da):52,729
Last modified:November 1, 1997 - v4
Checksum:i047EBB65D9B8F133
GO

Sequence cautioni

The sequence AAB03001 differs from that shown. Reason: Erroneous initiation. Translation N-terminally shortened.Curated

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti232L → V in CAA57578 (PubMed:7768836).Curated1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
D16509 Genomic DNA Translation: BAA03961.1
X82073 Genomic DNA Translation: CAA57578.1
L19201 Genomic DNA Translation: AAB03001.1 Different initiation.
U00096 Genomic DNA Translation: AAC76864.2
AP009048 Genomic DNA Translation: BAE77442.1
RefSeqiNP_418303.2, NC_000913.3
WP_000116090.1, NZ_LN832404.1

Genome annotation databases

EnsemblBacteriaiAAC76864; AAC76864; b3867
BAE77442; BAE77442; BAE77442
GeneIDi948362
KEGGiecj:JW3838
eco:b3867
PATRICifig|1411691.4.peg.2845

Similar proteinsi

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
D16509 Genomic DNA Translation: BAA03961.1
X82073 Genomic DNA Translation: CAA57578.1
L19201 Genomic DNA Translation: AAB03001.1 Different initiation.
U00096 Genomic DNA Translation: AAC76864.2
AP009048 Genomic DNA Translation: BAE77442.1
RefSeqiNP_418303.2, NC_000913.3
WP_000116090.1, NZ_LN832404.1

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1OLTX-ray2.07A1-457[»]
ProteinModelPortaliP32131
SMRiP32131
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi4262627, 13 interactors
DIPiDIP-9887N
IntActiP32131, 7 interactors
STRINGi316385.ECDH10B_4057

Proteomic databases

PaxDbiP32131
PRIDEiP32131

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaiAAC76864; AAC76864; b3867
BAE77442; BAE77442; BAE77442
GeneIDi948362
KEGGiecj:JW3838
eco:b3867
PATRICifig|1411691.4.peg.2845

Organism-specific databases

EchoBASEiEB1782
EcoGeneiEG11836 hemN

Phylogenomic databases

eggNOGiENOG4105D4P Bacteria
COG0635 LUCA
HOGENOMiHOG000257214
InParanoidiP32131
KOiK02495
PhylomeDBiP32131

Enzyme and pathway databases

UniPathwayi
UPA00251;UER00323

BioCyciEcoCyc:HEMN-MONOMER
MetaCyc:HEMN-MONOMER
BRENDAi1.3.99.22 2026

Miscellaneous databases

EvolutionaryTraceiP32131
PROiPR:P32131

Family and domain databases

Gene3Di3.80.30.20, 1 hit
InterProiView protein in InterPro
IPR004558 Coprogen_oxidase_HemN
IPR034505 Coproporphyrinogen-III_oxidase
IPR006638 Elp3/MiaB/NifB
IPR010723 HemN_C
IPR007197 rSAM
IPR023404 rSAM_horseshoe
PANTHERiPTHR13932 PTHR13932, 1 hit
PfamiView protein in Pfam
PF06969 HemN_C, 1 hit
PF04055 Radical_SAM, 1 hit
PIRSFiPIRSF000167 HemN, 1 hit
SFLDiSFLDF00277 oxygen-independent_coproporphy, 1 hit
SFLDG01065 anaerobic_coproporphyrinogen-I, 1 hit
SFLDS00029 Radical_SAM, 2 hits
SMARTiView protein in SMART
SM00729 Elp3, 1 hit
TIGRFAMsiTIGR00538 hemN, 1 hit
ProtoNetiSearch...

Entry informationi

Entry nameiHEMN_ECOLI
AccessioniPrimary (citable) accession number: P32131
Secondary accession number(s): P76772, Q2M8G4
Entry historyiIntegrated into UniProtKB/Swiss-Prot: October 1, 1993
Last sequence update: November 1, 1997
Last modified: November 7, 2018
This is version 157 of the entry and version 4 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. SIMILARITY comments
    Index of protein domains and families
  2. PATHWAY comments
    Index of metabolic and biosynthesis pathways
  3. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  4. Escherichia coli
    Escherichia coli (strain K12): entries and cross-references to EcoGene
UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health

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