Gamma thionin

Pfam_box
Symbol = Gamma-thionin
Name =

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width =210
caption = Antifungal protein 1
Pfam= PF00304
InterPro= IPR008176
SMART=
PROSITE = PDOC00725
SCOP = 1gps
TCDB =
OPM family= 61
OPM protein= 1jkz
PDB=PDB3|1gpt :1-47 PDB3|1gps :1-47 PDB3|1ti5A:28-73PDB3|1mr4A:26-72 PDB3|1n4nA:26-72 PDB3|1h3rA:28-72PDB3|1jkzA:1-46 PDB3|1myn :27-70 PDB3|1ayj :2-51PDB3|1bk8 :4-50

Gamma-thionins (also known as plant defensins) are small evolutionarily related proteins of plants that serves for their defense from parasites.

The following plant proteins are belong to this family:

* Gamma-thionins from "Triticum aestivum" (Wheat) endosperm (gamma-purothionins) and gamma-hordothionins from "Hordeum vulgare"(Barley) are toxic to animal cells and inhibit protein synthesis in cell free systemscite journal |author=Bruix M, Jimenez MA, Santoro J, Gonzalez C, Colilla FJ, Mendez E, Rico M |title=Solution structure of gamma 1-H and gamma 1-P thionins from barley and wheat endosperm determined by 1H-NMR: a structural motif common to toxic arthropod proteins |journal=Biochemistry |volume=32 |issue=2 |pages=715–724 |year=1993 |pmid=8380707 |doi=10.1021/bi00053a041] .
* A flower-specific thionin (FST) from "Nicotiana tabacum" (Common Tobacco)cite journal |author=Gu Q, Kawata EE, Cheung AY, Morse MJ, Wu HM |title=A flower-specific cDNA encoding a novel thionin in tobacco |journal=Mol. Gen. Genet. |volume=234 |issue=1 |pages=89–96 |year=1992 |pmid=1495489] .
* Antifungal proteins (AFP) from the seeds of Brassicaceae species such as radish, mustard, turnip and "Arabidopsis thaliana" (Thale Cress)cite journal |author=Osborn RW, Torrekens S, Vanderleyden J, Broekaert WF, Cammue BP, Terras FR, Van Leuven F |title=A new family of basic cysteine-rich plant antifungal proteins from Brassicaceae species |journal=FEBS Lett. |volume=316 |issue=3 |pages=233–240 |year=1993 |pmid=8422949 |doi=10.1016/0014-5793(93)81299-F] .
* Inhibitors of insect alpha-amylases from sorghumcite journal |author=Richardson M, Bloch Jr C |title=A new family of small (5 kDa) protein inhibitors of insect alpha-amylases from seeds or sorghum (Sorghum bicolar (L) Moench) have sequence homologies with wheat gamma-purothionins |journal=FEBS Lett. |volume=279 |issue=1 |pages=101–104 |year=1991 |pmid=1995329 |doi=10.1016/0014-5793(91)80261-Z] .
* Probable protease inhibitor P322 from "Solanum tuberosum" (Potato).
* A germination-related protein from "Vigna unguiculata" (Cowpea)cite journal |author=Ishibashi N, Yamauchi D, Minamikawa T |title=Stored mRNA in cotyledons of Vigna unguiculata seeds: nucleotide sequence of cloned cDNA for a stored mRNA and induction of its synthesis by precocious germination |journal=Plant Mol. Biol. |volume=15 |issue=1 |pages=59–64 |year=1990 |pmid=2103443 |doi=10.1007/BF00017724] .
* Anther-specific protein SF18 from sunflower. SF18 is a protein that contains a gamma-thionin domain at its N-terminus and a proline-rich C-terminal domain.
* "Glycine max" (Soybean) sulfur-rich protein SE60cite journal |author=Choi Y, Choi YD, Lee JS |title=Nucleotide sequence of a cDNA encoding a low molecular weight sulfur-rich protein in soybean seeds |journal=Plant Physiol. |volume=101 |issue=2 |pages=699–700 |year=1993 |pmid=8278516 |doi=10.1104/pp.101.2.699] .
* "Vicia faba" (Broad bean) antibacterial peptides fabatin-1 and -2.

In their mature form, these proteins generally consist of about 45 to 50 amino-acid residues. As shown in the following schematic representation, these peptides contain eight conserved cysteines involved in disulfide bonds.

+-------------------------------------------+
+-------------------+
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xxCxxxxxxxxxxCxxxxxCxxxCxxxxxxxxxCxxxxxxCxCxxxC
| |
+---|----------------+

'C': conserved cysteine involved in a disulfide bond.

The folded structure of Gamma-purothionin is characterised by a well-defined 3-stranded anti-parallel beta-sheet and a short alpha-helix. Three disulfide bridges are located in the hydrophobic core between the helix and sheet, forming a cysteine-stabilised alpha-helical motif. This structure differs from that of the plant alpha- and beta-thionins, but is analogous to scorpion toxins and insect defensins.

Databases

A database for antimicrobial peptides, including defensins is available: PhytAMP (http://phytamp.pfba-lab.org) [cite journal |author=Hammami R, Ben Hamida J, Vergoten G, Fliss I, |title=PhytAMP: a database dadicated to plant antimicrobial peptides.|journal=Nucleic Acid Research |year=2008 |pmid=18836196 |doi=10.1093/nar/gkn655] .

References

ubfamilies

*Gamma Purothionin InterPro|IPR008177