PROSITE documentation PDOC00286
Thaumatin family signature and profile


Thaumatin [1] is an intensely sweet-tasting protein (100 000 times sweeter than sucrose on a molar basis) found in berries from Thaumatococcus daniellii, an African bush. The protein consists of about 200 residues and contains 8 disulfide bonds. Several stress-induced proteins of plants have been found to be related to thaumatins. Some of these proteins are listed below.

  • A maize α-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.
  • Osmotin-like proteins OSML13, OSML15 and OSML81 from potato [2].
  • P21, a leaf protein from soybean.
  • PWIR2, a leaf protein from wheat.
  • Zeamatin, a maize antifunal protein [3].

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. As a signature pattern, we selected a conserved region that includes three cysteine residues known to be involved in disulfide bonds.

   |                                          +-----------------+         |
   |                  *******                 |                 |         |
                    |  |  | |              |    |   | |  || |         |
                    +--+  +-+              |    +---+ +--++-+         |
'C': conserved cysteine involved in a disulfide bond.
'*': position of the pattern.

We also developed a profile that covers the whole structure [4] of thaumatin/osmotin/PR5a.

Last update:

February 2008 / Text revised; profile added.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

THAUMATIN_2, PS51367; Thaumatin family profile  (MATRIX)

THAUMATIN_1, PS00316; Thaumatin family signature  (PATTERN)


1AuthorsEdens L. Heslinga L. Klok R. Ledeboer A.M. Maat J. Toonen M.Y. Visser C. Verrips C.T.
TitleCloning of cDNA encoding the sweet-tasting plant protein thaumatin and its expression in Escherichia coli.
SourceGene 18:1-12(1982).
PubMed ID7049841

2AuthorsZhu B. Chen T.H.H. Li P.H.
TitleActivation of two osmotin-like protein genes by abiotic stimuli and fungal pathogen in transgenic potato plants.
SourcePlant Physiol. 108:929-937(1995).
PubMed ID7630973

3AuthorsMalehorn D.E. Borgmeyer J.R. Smith C.E. Shah D.M.
TitleCharacterization and expression of an antifungal zeamatin-like protein (Zlp) gene from Zea mays.
SourcePlant Physiol. 106:1471-1481(1994).
PubMed ID7846159

4AuthorsKoiwa H. Kato H. Nakatsu T. Oda J. Yamada Y. Sato F.
TitleCrystal structure of tobacco PR-5d protein at 1.8 A resolution reveals a conserved acidic cleft structure in antifungal thaumatin-like proteins.
SourceJ. Mol. Biol. 286:1137-1145(1999).
PubMed ID10047487

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