Study of allosteric communication between protomers by immunotagging

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Allosteric regulation is crucial for protein function and cellular processes.
• Distinguishing between concerted and sequential allosteric mechanisms is challenging.
• Type II DNA topoisomerases are essential enzymes involved in DNA replication and repair.

Purpose of the Study:

• To investigate the allosteric communication between subunits in type II DNA topoisomerases.
• To determine if ATP binding to one protomer induces a concerted conformational change in the entire enzyme.
• To develop a generalizable method for studying allostery in macromolecular assemblies.

Main Methods:

• Utilized a modified type II DNA topoisomerase with one wild-type subunit and one immunotagged subunit defective in ATP binding.
• Investigated the coupling between ATP hydrolysis and DNA transport.
• Applied biochemical assays to analyze enzyme activity and conformational changes.

Main Results:

• Demonstrated that ATP binding to one protomer of type II DNA topoisomerase can indeed induce a concerted conformational change in the entire enzyme.
• Provided evidence for efficient allosteric communication within the dimeric enzyme.
• Established a novel experimental approach for studying allosteric mechanisms.

Conclusions:

• ATP binding in type II DNA topoisomerases triggers a coordinated conformational response across the entire enzyme.
• This study provides a powerful new method for investigating allostery and inter-subunit communication in complex molecular machines.
• The findings have broad implications for understanding enzyme regulation and designing novel therapeutics.