MEERCAT: Multiplexed Efficient Cell Free Expression of Recombinant QconCATs For Large Scale Absolute Proteome...

Area of Science:

• Proteomics
• Biotechnology
• Molecular Biology

Background:

• Accurate absolute quantification of numerous proteins is a significant challenge in proteomics.
• Quantitative standards, such as QconCATs (quantitative C-terminal concatenated standards), are crucial for precise proteome analysis.
• Traditional bacterial expression systems for QconCATs have limitations, including expression failures and proteolytic degradation.

Purpose of the Study:

• To develop and validate a robust cell-free expression system for QconCATs.
• To overcome limitations associated with bacterial expression of QconCATs.
• To enable highly multiplexed synthesis of QconCATs for large-scale proteome quantification.

Main Methods:

• Utilized a cell-free protein synthesis system for QconCAT expression.
• Implemented a highly multiplexed translation reaction for simultaneous coexpression of multiple QconCATs.
• Optimized conditions to rescue previously unexpressed QconCATs and minimize proteolytic damage.

Main Results:

• Successfully expressed QconCATs in a cell-free system, rescuing proteins that failed in bacterial expression.
• Reduced proteolytic damage to QconCATs compared to bacterial methods.
• Achieved simultaneous coexpression of tens to hundreds of QconCATs, enabling the generation of tens of thousands of standard peptides within weeks.
• Demonstrated a reproducible and broadly deployable system for absolute proteome quantification.

Conclusions:

• Cell-free expression offers a superior alternative to bacterial systems for QconCAT production.
• High-level multiplexing in cell-free systems dramatically accelerates the generation of protein standards.
• This approach makes absolute quantification of complex proteomes highly achievable, reproducible, and broadly deployable.