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Updated: Jul 12, 2026
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Exploring Sequence Space to Identify Binding Sites for Regulatory RNA-Binding Proteins
Published on: August 9, 2019
Protein Surface Site Determines the Evolutionary Accessibility of Allosteric Regulation
Jerry C Dinan1,2,3, James W McCormick1,2,3, Rishi Soni4
1The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390.
Biorxiv : the Preprint Server for Biology
|July 10, 2026
Summary
Protein surface context dictates the emergence of new allosteric regulation. Inserting a domain into a sector-connected surface enables light-dependent allostery, while non-sector sites are evolutionarily inert for this regulatory phenotype.
Area of Science:
- Protein engineering
- Molecular biology
- Biophysics
Background:
- Domain recombination is a key driver of allosteric regulation evolution.
- Understanding the factors governing the emergence of new allosteric sites is crucial for protein design.
- Protein sectors represent pre-existing cooperative networks on protein surfaces.
Purpose of the Study:
- To investigate if local protein surface context, specifically connection to protein sectors, influences the evolutionary accessibility of allosteric regulation after domain insertion.
- To compare the evolvability of allosteric regulation in synthetic protein chimeras with different surface contexts.
Main Methods:
- Construction of two synthetic protein chimeras by inserting the light-oxygen-voltage (LOV2) domain into dihydrofolate reductase (DHFR) at sector-connected and non-sector-connected sites.
- Characterization of allosteric regulation and catalytic activity in the engineered DHFR variants.
- Deep mutational scanning to identify single point mutations affecting allosteric regulation in both chimeras.
Main Results:
- The sector-connected chimera (DL121) exhibited light-dependent allostery and was highly evolvable, with numerous mutations tuning allostery.
- The non-sector-connected chimera (DL116) lacked significant allosteric regulation and evolvability, suggesting an evolutionarily inert surface.
- DL116 did not display cooperative unfolding even at high temperatures, indicating stability does not directly correlate with allosteric evolvability.
Conclusions:
- Protein surface context significantly constrains the evolutionary pathways for developing allosteric regulation.
- Sector-connected surfaces possess a latent capacity for allosteric regulation, while non-sector sites are less amenable to evolving this phenotype.
- The findings support the role of protein sectors in facilitating the emergence of novel allosteric functions.
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