O05927 · CYSH_PSEAE

Function

function

Catalyzes the formation of sulfite from adenosine 5'-phosphosulfate (APS) using thioredoxin as an electron donor.

Caution

The [4Fe-4S] cluster was originally thought to be ligated by three cysteine residues, but the crystal structure establishes that it is ligated by four cysteine residues.

Catalytic activity

Cofactor

[4Fe-4S] cluster (UniProtKB | Rhea| CHEBI:49883 )

Note: Binds 1 [4Fe-4S] cluster per subunit (PubMed:11940598, PubMed:15491155, PubMed:16289027, PubMed:17010373).
The cluster is required for activity and may play a role in binding and activating the substrate for thiol-mediated reduction (PubMed:15491155, PubMed:16289027, PubMed:17010373).

Kinetics

KM SUBSTRATE pH TEMPERATURE[C] NOTES EVIDENCE
1.75 μM5'-adenylyl sulfate8.530
19.6 μMthioredoxin8.530
Vmax pH TEMPERATURE[C] NOTES EVIDENCE
5.8 μmol/min/mg8.530with thioredoxin as electron donor and 5'-adenylyl sulfate as substrate

pH Dependence

Optimum pH is 8.5.

Pathway

Sulfur metabolism; hydrogen sulfide biosynthesis; sulfite from sulfate.

Features

Showing features for binding site, active site.

TypeIDPosition(s)Description
Binding site60adenosine 5'-phosphosulfate (UniProtKB | ChEBI)
Binding site85adenosine 5'-phosphosulfate (UniProtKB | ChEBI)
Binding site139[4Fe-4S] cluster (UniProtKB | ChEBI)
Binding site140[4Fe-4S] cluster (UniProtKB | ChEBI)
Binding site144adenosine 5'-phosphosulfate (UniProtKB | ChEBI)
Binding site161adenosine 5'-phosphosulfate (UniProtKB | ChEBI)
Binding site228[4Fe-4S] cluster (UniProtKB | ChEBI)
Binding site231[4Fe-4S] cluster (UniProtKB | ChEBI)
Binding site242-245adenosine 5'-phosphosulfate (UniProtKB | ChEBI)
Active site256Nucleophile; cysteine thiosulfonate intermediate

GO annotations

AspectTerm
Cellular Componentcytoplasm
Molecular Function4 iron, 4 sulfur cluster binding
Molecular Functionadenylyl-sulfate reductase (thioredoxin) activity
Molecular Functionmetal ion binding
Molecular Functionphosphoadenylyl-sulfate reductase (thioredoxin) activity
Biological Processcysteine biosynthetic process
Biological Processsulfate assimilation
Biological Processsulfate assimilation, phosphoadenylyl sulfate reduction by phosphoadenylyl-sulfate reductase (thioredoxin)

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Adenosine 5'-phosphosulfate reductase
  • EC number
  • Short names
    APS reductase
  • Alternative names
    • 5'-adenylylsulfate reductase
    • Thioredoxin-dependent 5'-adenylylsulfate reductase

Gene names

    • Name
      cysH
    • Ordered locus names
      PA1756

Organism names

Accessions

  • Primary accession
    O05927

Proteomes

Organism-specific databases

Subcellular Location

Keywords

Phenotypes & Variants

Disruption phenotype

Cysteine auxotrophy.

Features

Showing features for mutagenesis.

TypeIDPosition(s)Description
Mutagenesis139Loss of activity. Contains essentially no iron.
Mutagenesis140Retains 3% of wild-type activity. Contains less iron and sulfide than the wild-type. Decreases stability of the iron-sulfur cluster.
Mutagenesis228Loss of activity. Contains essentially no iron.
Mutagenesis231Loss of activity. Contains essentially no iron.
Mutagenesis256Loss of activity. Has iron and sulfide contents very similar to those of the wild-type. Does not affect the stability of the iron-sulfur cluster.

PTM/Processing

Features

Showing features for chain, disulfide bond.

TypeIDPosition(s)Description
ChainPRO_00001006381-267Adenosine 5'-phosphosulfate reductase
Disulfide bond140↔256Redox-active

Keywords

Proteomic databases

Interaction

Subunit

Homotetramer.

Protein-protein interaction databases

Family & Domains

Features

Showing features for region, compositional bias.

TypeIDPosition(s)Description
Region1-25Disordered
Compositional bias10-24Polar residues

Domain

The two chemically discrete steps of the overall reaction take place at distinct sites on the enzyme, mediated via conformational flexibility of the C-terminal 18 residues.

Sequence similarities

Belongs to the PAPS reductase family. CysH subfamily.

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    267
  • Mass (Da)
    30,215
  • Last updated
    2000-12-08 v2
  • Checksum
    E9557E1970F21049
MLPFATIPATERNSAAQHQDPSPMSQPFDLPALASSLADKSPQDILKAAFEHFGDELWISFSGAEDVVLVDMAWKLNRNVKVFSLDTGRLHPETYRFIDQVREHYGIAIDVLSPDPRLLEPLVKEKGLFSFYRDGHGECCGIRKIEPLKRKLAGVRAWATGQRRDQSPGTRSQVAVLEIDGAFSTPEKPLYKFNPLSSMTSEEVWGYIRMLELPYNSLHERGYISIGCEPCTRPVLPNQHEREGRWWWEEATHKECGLHAGNLISKA

Features

Showing features for sequence conflict, compositional bias.

TypeIDPosition(s)Description
Sequence conflict2in Ref. 1; AAB53743
Compositional bias10-24Polar residues

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
U95379
EMBL· GenBank· DDBJ
AAB53743.1
EMBL· GenBank· DDBJ
Genomic DNA
AE004091
EMBL· GenBank· DDBJ
AAG05145.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

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