Please note: this site relies heavily on the use of javascript. Without a javascript-enabled browser, this site will not function correctly. Please enable javascript and reload the page, or switch to a different browser.
50  structures 247  species 1  interaction 1409  sequences 29  architectures

Family: Thaumatin (PF00314)

Summary: Thaumatin family

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Thaumatin". More...

Thaumatin Edit Wikipedia article

Thaumatin family
Thaumatin I 1RQW.png
Cartoon diagram of thaumatin I. From PDB 1RQW.
Symbol Thaumatin
Pfam PF00314
InterPro IPR001938
SCOP 1thu
OPM superfamily 189
OPM protein 1aun
CDD cd09215
Thaumatin I
PDB 1RQW (RCSB PDB PDBe PDBj) More structures
UniProt P02883
Thaumatin II
UniProt P02884

Thaumatin is a low-calorie sweetener and flavour modifier. The protein is often used primarily for its flavour-modifying properties and not exclusively as a sweetener.[1]

The thaumatins were first found as a mixture of proteins isolated from the katemfe fruit (Thaumatococcus daniellii Bennett) of west Africa. Some proteins in the thaumatin family of sweeteners are roughly 2000 times more potent than sugar. Although very sweet, thaumatin's taste is markedly different from sugar's. The sweetness of thaumatin builds very slowly. Perception lasts a long time, leaving a liquorice-like aftertaste at high usage levels. Thaumatin is highly water soluble, stable to heating, and stable under acidic conditions.

Biological role[edit]

Thaumatin production is induced in katemfe in response to an attack upon the plant by viroid pathogens. Several members of the thaumatin protein family display significant in vitro inhibition of hyphal growth and sporulation by various fungi. The thaumatin protein is considered a prototype for a pathogen-response protein domain. This thaumatin domain has been found in species as diverse as rice and Caenorhabditis elegans. Thaumatins are pathogenesis-related (PR) proteins, which are induced by various agents ranging from ethylene to pathogens, and are structurally diverse and ubiquitous in plants:[2] They include thaumatin, osmotin, tobacco major and minor PR proteins, alpha-amylase/trypsin inhibitor, and P21 and PWIR2 soybean and wheat leaf proteins. The proteins are involved in systematically acquired resistance and stress response in plants, although their precise role is unknown.[2] Thaumatin is an intensely sweet-tasting protein (on a molar basis about 100,000 times as sweet as sucrose[3]) found in the West African shrub Thaumatococcus daniellii: it is induced by attack by viroids, which are single-stranded unencapsulated RNA molecules that do not code for protein. The thaumatin protein I consists of a single polypeptide chain of 207 residues.

Like other PR proteins, thaumatin is predicted to have a mainly beta structure, with a high content of beta-turns and little helix.[2] Tobacco cells exposed to gradually increased salt concentrations develop a greatly increased tolerance to salt, due to the expression of osmotin,[4] a member of the PR protein family. Wheat plants attacked by barley powdery mildew express a PR protein (PWIR2), which results in resistance against that infection.[5] The similarity between this PR protein and other PR proteins to the maize alpha-amylase/trypsin inhibitor has suggested PR proteins may act as some form of inhibitor.[5]

The thaumatin-like proteins isolated from kiwi fruit or apple appear to have their allergenic properties minimally reduced by gastroduodenal digestive processes, but not by heating.[6][7]


Within West Africa, the katemfe fruit has been locally cultivated and used to flavor foods and beverages for some time. The fruit's seeds are encased in a membranous sac, or aril, that is the source of thaumatin. In the 1970s, Tate and Lyle began extracting thaumatin from the fruit. In 1990, researchers at Unilever reported the isolation and sequencing of the two principal proteins found in thaumatin, which they dubbed thaumatin I and thaumatin II. These researchers were also able to express thaumatin in genetically engineered bacteria.

Thaumatin has been approved as a sweetener in the European Union (E957), Israel, and Japan. In the United States, it is a generally recognized as safe flavoring agent (FEMA GRAS 3732) but not as a sweetener.

Crystallization of thaumatin[edit]

Since thaumatin crystallizes rapidly and easily in the presence of tartrate ions, thaumatin-tartrate mixtures are frequently used as model systems to study protein crystallization. Interestingly, the solubility of thaumatin, its crystal habit, and mechanism of crystal formation is dependent upon the chirality of precipitant used. When crystallized with L- tartrate, thaumatin forms bipyramidal crystals and displays a solubility that increases with temperature; with D- and meso-tartrate, it forms stubby and prismatic crystals and displays a solubility that decreases with temperature.[8] This suggests control of precipitant chirality may be an important factor in protein crystallization in general.

See also[edit]


  1. ^ Green C (1999). "Thaumatin: a natural flavour ingredient". World Rev Nutr Diet. World Review of Nutrition and Dietetics 85: 129–32. doi:10.1159/000059716. ISBN 3-8055-6938-6. PMID 10647344. 
  2. ^ a b c Herrera-Estrella L, Ruiz-Medrano R, Jimenez-Moraila B, Rivera-Bustamante RF (1992). "Nucleotide sequence of an osmotin-like cDNA induced in tomato during viroid infection". Plant Mol. Biol. 20 (6): 1199–1202. doi:10.1007/BF00028909. PMID 1463856. 
  3. ^ Edens L, Heslinga L, Klok R, Ledeboer MNJ, Toonen MY, Visser C, Verrips CT (1982). "Cloning of cDNA encoding the sweet-tasting plant protein thaumatin and its expression in Escherichia coli". Gene 18 (1): 1–12. doi:10.1016/0378-1119(82)90050-6. PMID 7049841. 
  4. ^ Singh NK, Nelson DE, Kuhn D, Hasegawa PM, Bressan RA (1989). "Molecular Cloning of Osmotin and Regulation of Its Expression by ABA and Adaptation to Low Water Potential". Plant Physiol. 90 (3): 1096–1101. doi:10.1104/pp.90.3.1096. PMC 1061849. PMID 16666857. 
  5. ^ a b Rebmann G, Mauch F, Dudler R, Hertig C, Bull J (1991). "A wheat glutathione-S-transferase gene with transposon-like sequences in the promoter region". Plant Mol. Biol. 16 (6): 1089–1091. doi:10.1007/BF00016083. PMID 1650615. 
  6. ^ Bublin M, Radauer C, Knulst A, Wagner S, Scheiner O, Mackie AR, Mills EN, Breiteneder H., Effects of gastrointestinal digestion and heating on the allergenicity of the kiwi allergens Act d 1, actinidin, and Act d 2, a thaumatin-like protein. Mol Nutr Food Res. 2008 Oct;52(10):1130-9.
  7. ^ Smole U, Bublin M, Radauer C, Ebner C, Breiteneder H., Mal d 2, the thaumatin-like allergen from apple, is highly resistant to gastrointestinal digestion and thermal processing. Int Arch Allergy Immunol. 2008;147(4):289-98. Epub 2008 Jul 11.
  8. ^ Asherie, Ginsberg, Greenbaum, Blass and Knafo. Effects of Protein Purity and Precipitant Stereochemistry on the Crystallization of Thaumatin, Crystal Growth and Design, Volume 8, issue 12 (December 3, 2008), p. 4200-4207. ISSN: 1528-7483 DOI: 10.1021/cg800616q

Further reading[edit]

  • Higginbotham JD (1986). Gelardi RC, Nabors LO, ed. Alternative sweeteners. New York: M. Dekker, Inc. ISBN 0-8247-7491-4. 
  • Higginbotham J, Witty M (1994). Thaumatin. Boca Raton: CRC Press. ISBN 0-8493-5196-0. 

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Thaumatin family Provide feedback

No Pfam abstract.

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001938

Thaumatin [PUBMED:7049841] is an intensely sweet-tasting protein, 100 000 times sweeter than sucrose on a molar basis [PUBMED:7049841] found in berries from Thaumatococcus daniellii, a tropical flowering plant known as Katemfe, it is induced by attack by viroids, which are single-stranded unencapsulated RNA molecules that do not code for protein.

Thaumatin consists of about 200 residues and contains 8 disulphide bonds. Like other PR proteins, thaumatin is predicted to have a mainly beta structure, with a high content of beta-turns and little helix [PUBMED:7049841]. Several stress-induced proteins of plants have been found to be related to thaumatins:

  • A maize alpha-amylase/trypsin inhibitor
  • Two tobacco pathogenesis-related proteins: PR-R major and minor forms,which are induced after infection with viruses
  • Salt-induced protein NP24 from tomato
  • Osmotin, a salt-induced protein from tobacco
  • [PUBMED:16666857]
  • Osmotin-like proteins OSML13, OSML15 and OSML81 from potato [PUBMED:7630973]
  • P21, a leaf protein from soybean
  • PWIR2, a leaf protein from wheat [PUBMED:1650615]
  • Zeamatin, a maize antifunal protein [PUBMED:7846159]

This protein is also referred to as pathogenesis-related group 5 (PR5), as many thaumatin-like proteins accumulate in plants in response to infection by a pathogen and possess antifungal activity [PUBMED:1463856]. The proteins are involved in systematically acquired resistance and stress response in plants, although their precise role is unknown [PUBMED:1463856].

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

Loading domain graphics...


We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

Representative proteomes NCBI
Jalview View  View  View  View  View  View  View  View 
HTML View  View  View  View  View  View     
PP/heatmap 1 View  View  View  View  View     
Pfam viewer View  View             

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

Representative proteomes NCBI

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

Representative proteomes NCBI
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

Pfam alignments:

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...


This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Prosite
Previous IDs: thaumatin;
Type: Domain
Author: Finn RD
Number in seed: 124
Number in full: 1409
Average length of the domain: 174.60 aa
Average identity of full alignment: 39 %
Average coverage of the sequence by the domain: 73.41 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.7 21.7
Trusted cut-off 21.7 21.8
Noise cut-off 21.6 21.6
Model length: 213
Family (HMM) version: 12
Download: download the raw HMM for this family

Species distribution

Sunburst controls


This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

Loading sunburst data...

Tree controls


The tree shows the occurrence of this domain across different species. More...


Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.


There is 1 interaction for this family. More...



For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Thaumatin domain has been found. There are 50 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

Loading structure mapping...