Facile detection of peptide-protein interactions using an electrophoretic crosslinking shift assay.

Protein-protein interactions with high specificity and low affinity are functionally important but are not comprehensively understood because they are difficult to identify. Particularly intriguing are the dynamic and specific interactions between folded protein domains and short unstructured peptides known as short linear motifs. Such domain-motif interactions (DMIs) are often difficult to identify and study because affinities are modest to weak.

The structures of secretory and dimeric immunoglobulin A.

Secretory (S) Immunoglobulin (Ig) A is the predominant mucosal antibody, which binds pathogens and commensal microbes. SIgA is a polymeric antibody, typically containing two copies of IgA that assemble with one joining-chain (JC) to form dimeric (d) IgA that is bound by the polymeric Ig-receptor ectodomain, called secretory component (SC). Here, we report the cryo-electron microscopy structures of murine SIgA and dIgA.

Ndr/Lats Kinases Bind Specific Mob-Family Coactivators through a Conserved and Modular Interface.

Ndr/Lats kinases bind Mob coactivator proteins to form complexes that are essential and evolutionarily conserved components of "Hippo" signaling pathways, which control cell proliferation and morphogenesis in eukaryotes. All Ndr/Lats kinases have a characteristic N-terminal regulatory (NTR) region that binds a specific Mob cofactor: Lats kinases associate with Mob1 proteins, and Ndr kinases associate with Mob2 proteins. To better understand the significance of the association of Mob protein with Ndr/Lats kinases and selective binding of Ndr and Lats to distinct Mob cofactors, we determined crystal structures of Cbk1-Mob2 and Dbf2-Mob1 and experimentally assessed determinants of Mob cofactor binding and specificity.

Mapping low-affinity/high-specificity peptide-protein interactions using ligand-footprinting mass spectrometry.

Short linear peptide motifs that are intracellular ligands of folded proteins are a modular, incompletely understood molecular interaction language in signaling systems. Such motifs, which frequently occur in intrinsically disordered protein regions, often bind partner proteins with modest affinity and are difficult to study with conventional structural biology methods. We developed LiF-MS (ligand-footprinting mass spectrometry), a method to map peptide binding sites on folded protein domains that allows consideration of their dynamic disorder, and used it to analyze a set of D-motif peptide-mitogen-activated protein kinase (MAPK) associations to validate the approach and define unknown binding structures.

The RclR protein is a reactive chlorine-specific transcription factor in Escherichia coli.

Reactive chlorine species (RCS) such as hypochlorous acid are powerful antimicrobial oxidants. Used extensively for disinfection in household and industrial settings (i.e.

NemR is a bleach-sensing transcription factor.

Background: Little is known about how bacteria sense or respond to reactive chlorine species, such as bleach.

Results: NemR is a redox-regulated transcription factor which senses bleach.

Conclusion: NemR controls expression of genes encoding electrophile detoxification enzymes, which increase bleach resistance.