Evolution of oligomeric state through allosteric pathways that mimic ligand binding.

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Protein complex evolution and design traditionally focus on interface mutations.
• Residues distant from interfaces can allosterically influence protein oligomerization.
• The PyrR family of pyrimidine operon attenuators serves as a model system.

Purpose of the Study:

• To investigate the mechanism of allosteric mutations in protein complex formation.
• To understand how mutations distant from interfaces affect oligomeric state.
• To elucidate the role of conformational changes in allosteric regulation.

Main Methods:

• Analysis of the PyrR protein family.
• Identification of mutations controlling oligomeric state.
• Structural and conformational analysis.

Main Results:

• Identified 11 key mutations controlling oligomeric state in the PyrR family.
• These mutations are located far from protein-protein interaction interfaces and ligand-binding pockets.
• Key mutations induce conformational changes similar to those observed upon nucleotide binding.

Conclusions:

• Allosteric mutations can act from a distance to destabilize protein interfaces.
• Conformational changes are a key mechanism by which distant mutations regulate protein oligomerization.
• This finding broadens the understanding of protein complex evolution and design beyond direct interface interactions.