Functional dynamics in replication protein A DNA binding and protein recruitment domains

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Replication Protein A (RPA) is crucial for DNA replication, repair, and recombination.
• Its function depends on a modular architecture, particularly within the RPA70 subunit.
• Understanding the dynamics of RPA70's domains is key to elucidating its role in DNA processing.

Purpose of the Study:

• To characterize the dynamics of single-stranded DNA (ssDNA) binding and protein interaction modules within the RPA70 subunit.
• To investigate how ssDNA binding affects the coordinated motion of RPA70 domains.
• To determine the dynamic independence of the RPA70N and RPA70AB modules.

Main Methods:

• Utilized (15)N-nuclear magnetic resonance (NMR) heteronuclear relaxation analysis.
• Applied advanced NMR techniques to study protein dynamics at atomic resolution.
• Investigated the RPA70 subunit in the presence and absence of ssDNA substrate.

Main Results:

• Demonstrated coordinated motion between the tandem RPA70AB single-stranded DNA binding domains.
• Observed significant reorientation and coupled inter-domain motion upon ssDNA binding.
• Found the RPA70N protein interaction domain to be dynamically independent of RPA70AB, irrespective of ssDNA presence.

Conclusions:

• The dynamic autonomy of the 70N and 70AB modules supports independent mediation of RPA's binding functions.
• Differential coordination of domain motion, influenced by linker length, is proposed.
• Linkers between globular domains play a critical role in determining RPA's functional dynamics.