Q75N34 · DB3S_DIOPO

Function

function

Storage protein of tuber. Involved in protection against oxidative stress (Probable). Has carbonate dehydratase and weak trypsin inhibitor activity detected by measuring the dehydration of sodium bicarbonate and the inhibition of trypsin-catalyzed hydrolysis of N-benzoyl-L-arginine-4-nitro anilide, respectively (PubMed:10552514).
Contrarily, no carbonate dehydratase or trypsin inhibitor activity detected by measuring the hydrolysis of 4-nitrophenyl acetate or the inhibition of bovine trypsin-catalyzed hydrolysis of N-benzoyl-L-arginine ethyl ester, respectively (PubMed:15047697).
Has dehydroascorbate (DHA) reductase and monodehydroascorbate (MDA) reductase activities (Ref.5). Catalyzes the reactions of carbonate dehydratase and DHA reductase independently of zinc and glutathione (GSH). The coupled reaction is capable of recycling a plant antioxidant ascorbate using ubiquitous compounds H2O and CO2 (By similarity).
Exhibits antioxidant activity. Able to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl radicals (PubMed:11600050).
Exhibits immunomodulatory activity. Activates Toll-like receptor 4 signaling pathways by up-regulating the gene expression of pro-inflammatory cytokines, such as tumor necrosis factor alpha, interleukin-1 beta and interleukin-6, and chemokines RANTES and MCP-1, in mouse RAW 264.7 macrophages. Stimulates the phagocytosis of E.coli by the LPS-treated mouse macrophages (By similarity).

Caution

Despite overall sequence similarity to the typical alpha class carbonic anhydrases, lacks one of the three conserved catalytic zinc-ligand histidines. The carbonate dehydratase activity of this protein is zinc-independent.
It is uncertain whether the mature protein starts at position 22 or 23. The first residue of the N-terminus obtained by direct protein sequencing is 'Asn-22' according to PubMed:18303202, but it is 'Val-23' according to PubMed:15047697, PubMed:10552514 and PubMed:29423371.

Catalytic activity

Features

Showing features for active site, binding site.

TypeIDPosition(s)Description
Active site91Proton acceptor
Binding site92L-ascorbate (UniProtKB | ChEBI)
Binding site117-119L-ascorbate (UniProtKB | ChEBI)
Binding site136L-ascorbate (UniProtKB | ChEBI)
Binding site205-206L-ascorbate (UniProtKB | ChEBI)

GO annotations

AspectTerm
Molecular Functionantioxidant activity
Molecular Functioncarbonate dehydratase activity
Molecular FunctionL-ascorbic acid binding
Molecular Functionmonodehydroascorbate reductase (NADH) activity
Molecular Functionnutrient reservoir activity
Molecular Functionprotein homodimerization activity
Molecular Functionserine-type endopeptidase inhibitor activity
Molecular Functionzinc ion binding
Biological Processcarbon utilization
Biological Processcellular oxidant detoxification
Biological Processcellular response to carbon dioxide
Biological Processnegative regulation of endopeptidase activity
Biological Processone-carbon metabolic process
Biological Processpositive regulation of gene expression
Biological Processpositive regulation of phagocytosis
Biological Processresponse to oxygen radical

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

  • Recommended name
    Dioscorin DB3S
  • EC number
  • Alternative names
    • Tuber storage protein DB3S
  • Allergen name
    Dio p TSP

Gene names

    • Name
      DB3S

Organism names

  • Taxonomic identifier
  • Taxonomic lineage
    Eukaryota > Viridiplantae > Streptophyta > Embryophyta > Tracheophyta > Spermatophyta > Magnoliopsida > Liliopsida > Dioscoreales > Dioscoreaceae > Dioscorea

Accessions

  • Primary accession
    Q75N34

Phenotypes & Variants

Allergenic properties

Causes an allergic reaction in human. Binds to IgE of patients allergic to Chinese yam (PubMed:18303202, PubMed:29423371).
Patients can be sensitized to this protein via an oral or inhalant route (PubMed:18303202).
Thermal stable oral allergen, which can to trigger anaphylactic reaction and oral allergy syndrome even when consumed as cooked. Activates human basophils (PubMed:29423371).

Keywords

Protein family/group databases

PTM/Processing

Features

Showing features for chain, signal, disulfide bond.

TypeIDPosition(s)Description
ChainPRO_5004286658?-268Dioscorin DB3S
Signal1-?
Disulfide bond50↔209

Post-translational modification

Not glycosylated.

Keywords

Expression

Tissue specificity

Expressed in tuber (at protein level).

Interaction

Subunit

Monomer (By similarity).
Homodimer (PubMed:15047697).

Structure

Family & Domains

Features

Showing features for domain.

TypeIDPosition(s)Description
Domain25-259Alpha-carbonic anhydrase

Sequence similarities

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Sequence processing
    The displayed sequence is further processed into a mature form.
  • Length
    268
  • Mass (Da)
    30,460
  • Last updated
    2004-07-05 v1
  • Checksum
    30F2BC9D273FCB30
MSSSTLLHLLLLSSLLFSCLANVEDEFSYIEGNPNGPENWGNLKPEWETCGKGMEQSPIQLRDNRVIFDQTLGRLRRNYRAVDARLRNSGHDVLVEFKGNAGSLSINRVAYQLKRIHFHSPSEHEMNGERFDLEAQLVHESQDQKRAVVSILFIFGRADPFLSDLEDFIKQFSSSQKNEINAGVVDPNQLQIDDSAYYRYMGSFTAPPCTEGISWTVMRKVATVSPRQVLLLKQAVNENAINNARPLQPTNFRSVFYFEQLKSKVCAI

Features

Showing features for sequence conflict.

TypeIDPosition(s)Description
Sequence conflict35in Ref. 4; AA sequence

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AB178473
EMBL· GenBank· DDBJ
BAD18021.1
EMBL· GenBank· DDBJ
mRNA

Similar Proteins

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