Thionin

Plant thionin
Wheat beta-purothionin. Alpha helices in red, beta sheets in blue, disulphide bridges in yellow. PDB: 1BHP​
Identifiers
Symbol	Thionin
Pfam	PF00321
InterPro	IPR001010
PROSITE	PDOC00244
SCOP2	1cnb / SCOPe / SUPFAM
TCDB	1.C.44
OPM superfamily	140
OPM protein	2plh
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary PDB 1BHP

Thionins are a family of small proteins found solely in higher plants. Typically, a thionin consists of 45–48 amino acid residues. 6–8 of these are cysteine forming 3–4 disulfide bonds. They include phoratoxins and viscotoxins.

Alpha- and beta- thionins are related to each other. The gamma thionins have a superficially similar structure but are an unrelated class of protein, now called plant defensins.