Abstract
Agrostemma githago L. (corn cockle) is an herbaceous plant mainly growing in Europe. The seeds of the corn cockle are toxic and poisonings were widespread in the past by consuming contaminated flour. The toxic principle of Agrostemma seeds was attributed to triterpenoid secondary metabolites. Indeed, this is in part true. However Agrostemma githago L. is also a producer of ribosome-inactivating proteins (RIPs). RIPs are N-glycosylases that inactivate the ribosomal RNA, a process leading to an irreversible inhibition of protein synthesis and subsequent cell death. A widely known RIP is ricin from Ricinus communis L., which was used as a bioweapon in the past. In this study we isolated agrostin, a 27 kDa RIP from the seeds of Agrostemma githago L., and determined its full sequence. The toxicity of native agrostin was investigated by impedance-based live cell imaging. By RNAseq we identified 7 additional RIPs (agrostins) in the transcriptome of the corn cockle. Agrostin was recombinantly expressed in E. coli and characterized by MALDI-TOF–MS and adenine releasing assay. This study provides for the first time a comprehensive analysis of ribosome-inactivating proteins in the corn cockle and complements the current knowledge about the toxic principles of the plant.
Highlights
Agrostemma githago L. is an annual herbaceous waist-height plant from the carnation family (Caryophyllaceae)
In addition to triterpene saponins the seeds of Agrostemma githago L. contain type I ribosome-inactivating proteins. These RIPs are N-glycosylases (EC 3.2.2.22) that remove an essential adenine ( A4324) from the 28S ribosomal RNA. This leads to an irreversible inhibition of protein synthesis and subsequent cell d eath[6]
Type I RIPs consist only of the N-glycosylase domain, whereas type II RIPs such as ricin from Ricinus communis L. contain a lectin domain which binds with high affinity to galactose molecules on the cell surface
Summary
Agrostemma githago L. (corn cockle) is an annual herbaceous waist-height plant from the carnation family (Caryophyllaceae). (corn cockle) is an annual herbaceous waist-height plant from the carnation family (Caryophyllaceae) It blooms in splendid pink-purple flowers—the name Agrostemma means “garland of the fields”. The Russian military commissariat allowed the consumption of maximally 5 g Agrostemma seeds per kg bread for a soldier. This was a dosage, which could already cause severe poisonings[1]. In addition to triterpene saponins the seeds of Agrostemma githago L. contain type I ribosome-inactivating proteins (type I RIPs). These RIPs are N-glycosylases (EC 3.2.2.22) that remove an essential adenine ( A4324) from the 28S ribosomal RNA. The physiological role of type I RIPs in the plant cell is not completely understood, they have been reported to provide protection against h erbivores[7,8] and viruses[9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
