Kinetic Competition Screening of Yeast-Displayed Libraries for Isolating High Affinity Binders

Area of Science:

• Biotechnology
• Molecular Biology
• Protein Engineering

Background:

• Yeast surface display is a powerful platform for generating high-affinity protein binders.
• Kinetic competition screening is crucial for improving binder affinity, especially when dissociation kinetics are critical.
• Maturing binders is essential for applications requiring high specificity and stability.

Purpose of the Study:

• To detail protocols for setting up and executing a kinetic competition screen.
• To demonstrate the application of this methodology for affinity maturation.
• To optimize binders for specific protein targets, focusing on dissociation rates.

Main Methods:

• Utilizing yeast surface display for binder selection and characterization.
• Implementing kinetic competition screening to assess and enhance binder-antigen interactions.
• Determining competition duration based on the parental clone's dissociation rate constant (k_off).

Main Results:

• Successfully improved the affinity of a viral double-stranded RNA binding protein.
• Achieved enhanced affinity in the sub-nanomolar range for the target protein.
• Validated the effectiveness of kinetic competition screening for affinity maturation.

Conclusions:

• Kinetic competition screening is a robust method for maturing protein binder affinity on yeast surface display.
• The described protocols provide a framework for optimizing binders with fast dissociation rates.
• This technique is valuable for developing high-affinity binders for various biological targets.