A combinatorial amino acid code for RNA recognition by pentatricopeptide repeat proteins.

Area of Science:

• Molecular Biology
• Genetics

Background:

• Pentatricopeptide repeat (PPR) proteins are a large family involved in gene expression within mitochondria and chloroplasts.
• PPR proteins contain 2-30 repeats and bind single-stranded RNA with sequence specificity, but the recognition mechanism was unclear.

Purpose of the Study:

• To elucidate the molecular basis of sequence-specific RNA recognition by PPR proteins.
• To develop a predictive model for PPR-RNA interactions.

Main Methods:

• Computational methods were employed to infer a nucleotide recognition code based on amino acids within PPR repeats.
• The computational model was experimentally validated by recoding a PPR protein for novel RNA binding in vitro.

Main Results:

• A modular recognition mechanism for PPR-RNA binding was identified, distinct from previously known modes.
• The study revealed an unprecedented diversity and size of natural PPR-RNA binding partners.
• The findings significantly advance the ability to predict native binding sites for PPR proteins.

Conclusions:

• The discovered PPR-RNA recognition code provides a framework for understanding and predicting interactions.
• The inherent plasticity of the PPR family allows for redesign, opening avenues for new functionalities.