Expanding the binding specificity for RNA recognition by a PUF domain

Area of Science:

• Protein Engineering
• Molecular Biology
• RNA-Binding Proteins

Background:

• The Pumilio (PUF) domain's modular structure allows for engineering novel RNA-binding specificities.
• Targeted protein-RNA interactions are crucial for numerous biological applications.
• Understanding the rules governing PUF-RNA recognition is key to designing custom binders.

Purpose of the Study:

• To generate libraries of PUF domain variants with altered amino acid residues critical for RNA contact.
• To establish an RNA binding code for individual PUF domain repeats.
• To design novel PUF domains with specific RNA-binding capabilities.

Main Methods:

• Creation of large-scale libraries (8,000 combinations) of amino acid substitutions within PUF domain repeats.
• Yeast three-hybrid selection assays to screen for PUF variants binding to specific RNA sequences.
• High-throughput sequencing to quantify binding affinity and specificity of variant interactions.

Main Results:

• Identification of numerous PUF variants exhibiting highly repeat-specific interactions with RNA.
• Development of a comprehensive RNA binding code detailing base-specific recognition for each PUF repeat.
• Successful design of novel PUF domains that recognize target RNAs with up to four sequence variations from the wild type.

Conclusions:

• The study demonstrates a systematic approach to engineering RNA-binding specificity in PUF domains.
• The derived RNA binding code provides a powerful tool for rational design of RNA-targeting proteins.
• Engineered PUF domains show potential for applications requiring precise RNA recognition.