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167  structures 727  species 0  interactions 7308  sequences 166  architectures

Family: Thaumatin (PF00314)

Summary: Thaumatin family

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Thaumatin Edit Wikipedia article

Thaumatin family
Thaumatin I 1RQW.png
Ribbon[1][2] diagram of thaumatin I. From PDB: 1RQW​.
OPM superfamily168
OPM protein1aun
Thaumatin I
OrganismThaumatococcus daniellii
Thaumatin II
OrganismThaumatococcus daniellii
PDB3wou (ECOD)

Thaumatin (also known as talin) 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.[3]

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

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:[4] 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.[4] Thaumatin is an intensely sweet-tasting protein (on a molar basis about 100,000 times as sweet as sucrose[5]) 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.[4] Tobacco cells exposed to gradually increased salt concentrations develop a greatly increased tolerance to salt, due to the expression of osmotin,[6] 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.[7] 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.[7]

Thaumatin crystal (~1 mm long) grown by liquid–liquid diffusion under a micro-g environment in outer space. Arrow marks nucleation point.[8]

Within West Africa, the katemfe fruit has been locally cultivated and used to flavour 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 generally recognized as safe as a flavouring agent (FEMA GRAS 3732) but not as a sweetener.

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.[9][10]



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. The solubility of thaumatin, its crystal habit, and mechanism of crystal formation are 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.[11] This suggests control of precipitant chirality may be an important factor in protein crystallization in general.


As a food ingredient, thaumatin is considered to be safe for consumption.[12][13] In a Swiss chewing gum production plant Thaumatin has been identified as allergen. Thaumatin powder led to allergic symptoms in the upper airways in occupationally exposed individuals. After the factory replaced powdered thaumatin with a liquid form, all of the affected individuals became completely free of symptoms.[14]

Thaumatin interacts with human TAS1R3 to produce a sweet taste. The interacting residues are specific to old world monkeys and apes (including humans), so only these animals can perceive it as sweet.[15]

See also

  • Curculin, a sweet protein from Malaysia with taste-modifying activity
  • Miraculin, a protein from West Africa with taste-modifying activity
  • Monellin, a sweet protein found in West Africa
  • Stevia, a 0 calorie sweetener up to 150 times sweeter than sugar


  1. ^ Stivala A, Wybrow M, Wirth A, Whisstock JC, Stuckey PJ (December 2011). "Automatic generation of protein structure cartoons with Pro-origami". Bioinformatics. 27 (23): 3315–6. doi:10.1093/bioinformatics/btr575. PMID 21994221.
  2. ^ DeLano Scientific LLC. (2004). Cartoon Representations.
  3. ^ Green C (1999). "Thaumatin: a natural flavour ingredient". Low-Calories Sweeteners: Present and Future. World Review of Nutrition and Dietetics. 85. pp. 129–32. doi:10.1159/000059716. ISBN 3-8055-6938-6. PMID 10647344.
  4. ^ a b c Ruiz-Medrano R, Jimenez-Moraila B, Herrera-Estrella L, Rivera-Bustamante RF (December 1992). "Nucleotide sequence of an osmotin-like cDNA induced in tomato during viroid infection". Plant Molecular Biology. 20 (6): 1199–202. doi:10.1007/BF00028909. PMID 1463856.
  5. ^ Edens L, Heslinga L, Klok R, Ledeboer AM, Maat J, Toonen MY, Visser C, Verrips CT (April 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.
  6. ^ Singh NK, Nelson DE, Kuhn D, Hasegawa PM, Bressan RA (July 1989). "Molecular Cloning of Osmotin and Regulation of Its Expression by ABA and Adaptation to Low Water Potential". Plant Physiology. 90 (3): 1096–101. doi:10.1104/pp.90.3.1096. PMC 1061849. PMID 16666857.
  7. ^ a b Mauch F, Hertig C, Rebmann G, Bull J, Dudler R (June 1991). "A wheat glutathione-S-transferase gene with transposon-like sequences in the promoter region". Plant Molecular Biology. 16 (6): 1089–91. doi:10.1007/BF00016083. PMID 1650615.
  8. ^ McPherson A, DeLucas LJ (2015). "Microgravity protein crystallization". NPJ Microgravity. 1: 15010. doi:10.1038/npjmgrav.2015.10. PMC 5515504. PMID 28725714.
  9. ^ Bublin M, Radauer C, Knulst A, Wagner S, Scheiner O, Mackie AR, et al. (October 2008). "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". Molecular Nutrition & Food Research. 52 (10): 1130–9. doi:10.1002/mnfr.200700167. PMID 18655003.
  10. ^ Smole U, Bublin M, Radauer C, Ebner C, Breiteneder H (2008). "Mal d 2, the thaumatin-like allergen from apple, is highly resistant to gastrointestinal digestion and thermal processing". International Archives of Allergy and Immunology. 147 (4): 289–98. doi:10.1159/000144036. PMID 18617748.
  11. ^ Asherie N, Ginsberg C, Greenbaum A, Blass S, Knafo S (2008). "Effects of Protein Purity and Precipitant Stereochemistry on the Crystallization of Thaumatin". Crystal Growth & Design. 8 (12): 4200. doi:10.1021/cg800616q.
  12. ^ Higginbotham JD, Snodin DJ, Eaton KK, Daniel JW (December 1983). "Safety evaluation of thaumatin (Talin protein)". Food and Chemical Toxicology. 21 (6): 815–23. doi:10.1016/0278-6915(83)90218-1. PMID 6686588.
  13. ^ Green C (1999). "Thaumatin: a natural flavour ingredient". World Review of Nutrition and Dietetics. 85: 129–32. doi:10.1159/000059716. ISBN 3-8055-6938-6. PMID 10647344.
  14. ^ Tschannen MP, Glück U, Bircher AJ, Heijnen I, Pletscher C (July 2017). "Thaumatin and gum arabic allergy in chewing gum factory workers". American Journal of Industrial Medicine. 60 (7): 664–669. doi:10.1002/ajim.22729. PMID 28543634.
  15. ^ Masuda T, Taguchi W, Sano A, Ohta K, Kitabatake N, Tani F (July 2013). "Five amino acid residues in cysteine-rich domain of human T1R3 were involved in the response for sweet-tasting protein, thaumatin". Biochimie. 95 (7): 1502–5. doi:10.1016/j.biochi.2013.01.010. hdl:2433/175269. PMID 23370115.

Further reading

  • Chang, Hsin-Yu. "The Sweetest Thing". InterPro Protein Focus.
  • Higginbotham JD (1986). Gelardi RC, Nabors LO (eds.). 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.

External links

  • Media related to Thaumatin at Wikimedia Commons

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

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Literature references

  1. Petre B, Major I, Rouhier N, Duplessis S;, BMC Plant Biol. 2011;11:33.: Genome-wide analysis of eukaryote thaumatin-like proteins (TLPs) with an emphasis on poplar. PUBMED:21324123 EPMC:21324123

Internal database links

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 antifungal protein [ PUBMED:7846159 ]

This family 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 systemically acquired resistance and stress response in plants, although their precise role is unknown [ PUBMED:1463856 ]. The PR5K receptor protein kinase from Arabidopsis comprises an extracellular domain related to the PR5 proteins, and an intracellular protein-serine/threonine kinase domain [ PUBMED:8637920 ].

Domain organisation

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

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Pfam Clan

This family is a member of clan CDC (CL0293), which has the following description:

This superfamily includes the MACPF domain as well as the Cholesterol-dependent cytolysins [1].

The clan contains the following 8 members:

Aegerolysin Anemone_cytotox FB_lectin Gasdermin MACPF TDH Thaumatin Thiol_cytolysin


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 (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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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
Sequence Ontology: SO:0000417
Author: Finn RD
Number in seed: 261
Number in full: 7308
Average length of the domain: 192.80 aa
Average identity of full alignment: 41 %
Average coverage of the sequence by the domain: 68.26 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 27.4 27.4
Trusted cut-off 27.4 27.4
Noise cut-off 27.3 27.3
Model length: 214
Family (HMM) version: 20
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Species distribution

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Archea Archea Eukaryota Eukaryota
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Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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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 167 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 sequence.

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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
A0A0N7KIK4 View 3D Structure Click here
A0A0N7KLX7 View 3D Structure Click here
A0A0N7KQ53 View 3D Structure Click here
A0A0P0VV61 View 3D Structure Click here
A0A0P0W1B6 View 3D Structure Click here
A0A0P0W889 View 3D Structure Click here
A0A0P0WDN5 View 3D Structure Click here
A0A0P0WGN4 View 3D Structure Click here
A0A0P0WQ76 View 3D Structure Click here
A0A0P0XF93 View 3D Structure Click here
A0A0P0XFC6 View 3D Structure Click here
A0A0P0XP28 View 3D Structure Click here
A0A0P0XWT5 View 3D Structure Click here
A0A0P0YCG8 View 3D Structure Click here
A0A0R0EVM0 View 3D Structure Click here
A0A0R0F1G5 View 3D Structure Click here
A0A0R0G700 View 3D Structure Click here
A0A0R0ITR8 View 3D Structure Click here
A0A0R0JGL8 View 3D Structure Click here
A0A0R0LK16 View 3D Structure Click here
A0A0R0LK39 View 3D Structure Click here
A0A1D6E0G6 View 3D Structure Click here
A0A1D6ESJ6 View 3D Structure Click here
A0A1D6GKZ3 View 3D Structure Click here
A0A1D6GWD8 View 3D Structure Click here
A0A1D6H9C7 View 3D Structure Click here
A0A1D6HVV4 View 3D Structure Click here
A0A1D6IQ00 View 3D Structure Click here
A0A1D6IQ04 View 3D Structure Click here
A0A1D6JVS5 View 3D Structure Click here
A0A1D6K1C3 View 3D Structure Click here
A0A1D6KBU1 View 3D Structure Click here
A0A1D6KE00 View 3D Structure Click here
A0A1D6KN64 View 3D Structure Click here
A0A1D6KUU7 View 3D Structure Click here
A0A1D6KZ34 View 3D Structure Click here
A0A1D6LHP8 View 3D Structure Click here
A0A1D6M2Z2 View 3D Structure Click here
A0A1D6MWV4 View 3D Structure Click here
A0A1D6N7J6 View 3D Structure Click here