InterPro domain: IPR044662

This entry represents a group of stress-response A/B barrel domain-containing proteins, including HS1 (also known as Protein HEAT STABLE 1 or Pop3 family protein At3g17210) and DABB1 from Arabidopsis thaliana [ 1 , 2 ]. Proteins in this family have two stress responsive dimeric A/B barrel domains (Dabb) whose function is not yet clear [ 3 ]. In general, stress-response A/B barrel domain-containing proteins in plants are involved in defense against fungal pathogens. This entry also includes Cannabis sativa olivetolic acid cyclase (OAC), which is an A/B barrel domain-containing protein structurally similar to HS1 and contains amino acid residues that are conserved in plant stress-responsive DABB proteins [ 3 ]. OAC functions in concert with OLS/TKS to form olivetolic acid, an alkylresorcinolic acid that forms the polyketide nucleus of the cannabinoids [ 4 ].

This entry also includes related proteins from bacteria and fungi.

1. Characterization of a heat-stable protein with antimicrobial activity from Arabidopsis thaliana. Biochem Biophys Res Commun 362, 562-7
2. Functional characterization of pathogen-responsive protein AtDabb1 with an antifungal activity from Arabidopsis thaliana. Biochim Biophys Acta 1784, 1918-23
3. Identification of olivetolic acid cyclase from Cannabis sativa reveals a unique catalytic route to plant polyketides. Proc Natl Acad Sci U S A 109, 12811-6