High-throughput protein characterization by complementation using DNA barcoded fragment libraries.

Area of Science:

• Genomics
• Molecular Biology
• Biochemistry

Background:

• Accurate gene function annotation is crucial for predicting, controlling, and designing biological systems.
• Challenges in functional annotation are amplified in non-model organisms, necessitating novel high-throughput methods.
• The study addresses the need for efficient and accurate functional characterization of proteins.

Purpose of the Study:

• To develop and validate a high-throughput method, Coaux-Seq, for characterizing protein function.
• To identify novel gene functions by complementing auxotrophic strains of Escherichia coli.
• To assess the effectiveness of Coaux-Seq across diverse bacterial genomes.

Main Methods:

• Utilized complementation of auxotrophs and DNA barcode sequencing (Coaux-Seq).
• Tested fragment libraries from eleven diverse bacterial species against twenty auxotrophic E. coli strains.
• Identified genes that restore metabolic function in auxotrophic strains.

Main Results:

• Recovered 41% of expected gene function complements.
• Demonstrated success with evolutionarily distant bacteria, including Bacillus subtilis and Bacteroides thetaiotaomicron.
• Provided first-time experimental validation for 53 proteins, including 11 with low sequence identity to known proteins.
• Identified novel functions such as sulfate transport, methionine synthesis, and aminotransferase activity.
• Observed instances of cross-feeding, where protein overexpression or neighboring strains facilitated growth.

Conclusions:

• Coaux-Seq is a robust and versatile high-throughput method for functional gene annotation.
• The method has significant potential for applications in microbial ecology, health, and synthetic biology.
• Coaux-Seq expands the functional annotation toolkit, particularly for non-model organisms.