PROSITE documentation PDOC00244
Plant thionins signature


Thionins are small, basic, plant proteins generally toxic to animal cells [1]. They seem to exert their toxic effect at the level of the cell membrane but their exact function is not known. They consist of a polypeptide chain of forty five to fifty amino acids with three to four internal disulfide bonds. They are found in seeds but also in the cell wall of leaves [2]. Thionins are processed from larger precursor proteins [3]. Crambin [4], a hydrophobic plant seed protein, also belongs to this family. The pattern we developed to detect this family of proteins includes three of the six cysteine residues involved in disulfide bonds.

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

The proteins from the γ-thionin family are not related to the above proteins and are described in a separate section.

Last update:

May 2004 / Text revised.


Technical section

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

THIONIN, PS00271; Plant thionins signature  (PATTERN)


1AuthorsVernon L.P. Evett G.E. Zeikus R.D. Gray W.R.
TitleA toxic thionin from Pyrularia pubera: purification, properties, and amino acid sequence.
SourceArch. Biochem. Biophys. 238:18-29(1985).
PubMed ID3985614

2AuthorsBohlmann H. Clausen S. Behnke S. Giese H. Hiller C. Reimann-Phillip U. Schrader G. Barkholt V. Apel K.
SourceEMBO J. 7:1559-1565(1988).

3AuthorsBohlmann H. Apel K.
SourceMol. Gen. Genet. 207:446-454(1987).

4AuthorsTeeter M.M. Mazer J.A. L'Italien J.J.
TitlePrimary structure of the hydrophobic plant protein crambin.
SourceBiochemistry 20:5437-5443(1981).
PubMed ID6895315

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