Dynamics and selective remodeling of the DNA-binding domains of RPA

Area of Science:

• Molecular biology
• Biochemistry
• Genetics

Background:

• Replication protein A (RPA) is crucial for DNA metabolism, stabilizing single-stranded DNA (ssDNA) intermediates.
• RPA possesses six DNA-binding domains (DBDs) that facilitate high-affinity ssDNA binding but can be displaced by proteins with lower affinity.
• Understanding RPA dynamics is key to comprehending DNA repair and replication processes.

Purpose of the Study:

• To visualize the conformational dynamics of individual DBDs within full-length Saccharomyces cerevisiae RPA.
• To investigate how RPA-interacting proteins access and remodel RPA-bound ssDNA.

Main Methods:

• Generation of fluorescently tagged Saccharomyces cerevisiae RPA.
• Real-time visualization of individual DBD conformational dynamics in full-length RPA.
• Analysis of RPA-ssDNA interactions and modulation by other proteins.

Main Results:

• Both DBD-A and DBD-D exhibit rapid binding and dissociation from ssDNA while RPA remains associated.
• The recombination mediator protein Rad52 specifically influences the dynamics of DBD-D.
• This dynamic remodeling allows lower-affinity proteins to access and potentially displace RPA from ssDNA.

Conclusions:

• RPA's individual DBDs possess distinct dynamic properties.
• Rad52's modulation of DBD-D dynamics is a key mechanism for RPA displacement.
• These findings elucidate how RPA-interacting proteins can remodel RPA-bound ssDNA, facilitating DNA metabolic events.