Year: 2023
Type: article
Abstract: In Escherichia coli, the single-stranded DNA-binding protein (SSB) acts as a genome maintenance organizational hub by interacting with multiple DNA metabolism proteins. Many SSB-interacting proteins (SIPs) form complexes with SSB by docking onto its carboxy-terminal tip (SSB-Ct). An alternative interaction mode in which SIPs bind to PxxP motifs within an intrinsically-disordered linker (IDL) in SSB has been proposed for the RecG DNA helicase and other SIPs. Here, RecG binding to SSB and SSB peptides was measured in vitro and the RecG/SSB interface was identified. The results show that RecG binds directly and specifically to the SSB-Ct, and not the IDL, through an evolutionarily conserved binding site in the RecG helicase domain. Mutations that block RecG binding to SSB sensitize E. coli to DNA damaging agents and induce the SOS DNA-damage response, indicating formation of the RecG/SSB complex is important in vivo. The broader role of the SSB IDL is also investigated. E. coli ssb mutant strains encoding SSB IDL deletion variants lacking all PxxP motifs retain wildtype growth and DNA repair properties, demonstrating that the SSB PxxP motifs are not major contributors to SSB cellular functions.
Source: Nucleic Acids Research
DOI: 10.1093/nar/gkad162
Institution: University of Wisconsin–Madison
Language: English
Topic: DNA Repair Mechanisms
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,630
Awards: Graduate Research Fellowship Program (GRFP), G3327790356, G4380079770, Biotechnology Training Program, Acquisition of Biophysics Instrumentation for Core Facility, ACQUISITION OF MASS SPECTROMETER FOR CORE FACILITY, G6864948768, G8393937582, Biotechnology Training Program, Creation and Repair of Postreplicative DNA Gaps
OpenAlex ID: W4324018024