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We are deeply saddened by the passing of Amos Bairoch (1957–2025), the creator of PROSITE. We wish to dedicate our latest paper, published shortly before his death, to him. He will always be a source of inspiration to us.
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Amos Bairoch

PROSITE documentation PDOC00244
Plant thionins signature


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PURL: https://purl.expasy.org/prosite/documentation/PDOC00244

Description

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.

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

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.

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Technical section

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

THIONIN, PS00271; Plant thionins signature  (PATTERN)


References

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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