This family represents a group of double-psi beta-barrel (DPBB) fold proteins similar to Barwin, including Wheatwin-1/-2, pathogenesis-related protein P2, and the C-terminal domains of Pro-hevein, Wound-induced proteins WIN1/WIN2, and hevein-like preproprotein. Barwin is a basic protein from barley seed. It is a probable plant lectin that may be involved in a defense mechanism. Barwin binds weakly to a chitin analog. Pro-hevein, also called major hevein, is a rubber tree N-acetyl-D-glucosamine/N-acetyl-D-neuraminic acid binding lectin that can inhibit fungal growth. WIN1 and WIN2 from potato are cysteine-rich proteins which show striking homology to several chitin-binding proteins. Wheatwin-1 and Wheatwin-2 from bread wheat are also called pathogenesis-related protein 4a and 4b, respectively. They show antifungal activity towards B. cinerea and towards the wheat-specific pathogenic fungi F. culmorum and F. graminearum (groups 1 and 2). Wheatwin-1 has ribonuclease activity. Pathogenesis-related protein P2 (also called PR protein P2) from tomato is homologous to WINs and pro-hevein, but lack the N-terminal, chitin-binding "hevein" domain. Hevein-like preproprotein (also called HEL protein) from Arabidopsis is a fungal growth inhibitor. Neither its N-terminal hevein-like domain (CB-HEL) nor the C-terminal domain (CD-HEL) have chitinase activity, but both have antimicrobial activities. CD-HEL has RNase, but no DNase activity.
Jiyao W et al.(2023). "The conserved domain database in 2023.",