Ribosome Inactivating Proteins from Rosaceae.

Area of Science:

• Plant molecular biology
• Biochemistry
• Genomics

Background:

• Ribosome-inactivating proteins (RIPs) are a diverse group of plant proteins.
• RIPs are known for their ability to inhibit protein synthesis.
• Their presence in Rosaceae species, including fruit crops, is of significant interest.

Purpose of the Study:

• To identify and characterize RIP sequences in the genomes/transcriptomes of Rosaceae species.
• To investigate the biological activity and structural properties of Rosaceae RIPs.
• To explore potential substrate interactions of these RIPs.

Main Methods:

• Bioinformatic analysis of Rosaceae genomes and transcriptomes to identify RIP sequences.
• Heterologous expression and purification of RIPs from apple (Malus domestica).
• Biochemical assays to assess protein synthesis inhibition.
• Molecular modeling to predict protein structures and substrate binding.
• Glycan array screening to identify RIP-carbohydrate interactions.

Main Results:

• RIP sequences, including type 1 and type 2, were identified across various Rosaceae species.
• RIP domains from Rosaceae exhibit high sequence similarity with conserved catalytic and carbohydrate-binding residues.
• Heterologously expressed apple RIPs (type 1 and type 2) demonstrated biological activity by inhibiting protein synthesis.
• Molecular modeling indicated that Rosaceae RIPs have structures similar to known RIPs and can bind substrates.
• A type 2 RIP from apple was found to interact with terminal sialic acid residues.

Conclusions:

• RIPs in Rosaceae species are evolutionarily conserved and possess conserved functional domains.
• The identified RIPs from Rosaceae, exemplified by apple RIPs, are biologically active and capable of inhibiting protein synthesis.
• Rosaceae RIPs likely possess conserved three-dimensional structures enabling substrate interaction.
• Specific RIPs, like the type 2 RIP from apple, show potential for specific glycan binding, suggesting diverse functional roles.