title: The IDL of E. coli SSB links ssDNA and protein binding by mediating protein-protein interactions.
abstract: The E. coli single strand DNA binding protein (SSB) is essential to viability where it functions in two seemingly disparate roles: it binds to single stranded DNA (ssDNA) and to target proteins that comprise the SSB interactome. The link between these roles resides in a previously under-appreciated region of the protein known as the intrinsically disordered linker (IDL). We present a model wherein the IDL is responsible for mediating protein-protein interactions critical to each role. When interactions occur between SSB tetramers, cooperative binding to ssDNA results. When binding occurs between SSB and an interactome partner, storage or loading of that protein onto the DNA takes place. The properties of the IDL that facilitate these interactions include the presence of repeats, a putative polyproline type II helix and, PXXP motifs that may facilitate direct binding to the OB-fold in a manner similar to that observed for SH3 domain binding of PXXP ligands in eukaryotic systems.
authors.affiliation: Department of Microbiology and Immunology, Center for Single Molecule Biophysics, University at Buffalo, Buffalo, New York, 14214.
authors.forename: Piero R
authors.initials: PR
authors.lastname: Bianco
authors.affiliation: Department of Microbiology and Immunology, Center for Single Molecule Biophysics, University at Buffalo, Buffalo, New York, 14214.
authors.forename: Sasheen
authors.initials: S
authors.lastname: Pottinger
authors.affiliation: Department of Microbiology and Immunology, Center for Single Molecule Biophysics, University at Buffalo, Buffalo, New York, 14214.
authors.forename: Hui Yin
authors.initials: HY
authors.lastname: Tan
authors.affiliation: Department of Microbiology and Immunology, Center for Single Molecule Biophysics, University at Buffalo, Buffalo, New York, 14214.
authors.forename: Trong
authors.initials: T
authors.lastname: Nguyenduc
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.
authors.forename: Kervin
authors.initials: K
authors.lastname: Rex
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.
authors.forename: Umesh
authors.initials: U
authors.lastname: Varshney
mesh_terms: D020816:Amino Acid Motifs; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D064267:Intrinsically Disordered Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D018909:src Homology Domains
chemical_list: D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D064267:Intrinsically Disordered Proteins; D010455:Peptides; C476430:SSB protein, E coli; C011083:polyproline
keywords: OB-fold; PXXP motif; RecG; RecO; SH3 domain; SSB