摘要：SummaryAs a promising target for alternative antimicrobials, bacterial recombinase A (RecA) protein has attracted much attention for its roles in antibiotic-driven SOS response and mutagenesis. Naphthalene polysulfonated compounds (NPS) such as suramin have previously been explored as antibiotic adjuvants targeting RecA, although the underlying structural bases for RecA-ligand interactions remain obscure. Based on ourin silicopredictions and documented activity of NPSin vitro, we conclude that the analyzed NPS likely interact with Tyr103 (Y103) and other key residues in the ATPase activity center (pocket A). For validation, we generated recombinant RecA proteins (wild-type versus Y103 mutant) to determine the binding affinities for RecA protein interactions with suramin and underexamined NPS in isothermal titration calorimetry. The corresponding dissociation constants (Kd) ranged from 11.5 to 18.8 μM, and Y103 was experimentally shown to be critical to RecA-NPS interactions.Graphical AbstractDisplay OmittedHighlights•RecA is conserved among major bacterial pathogens but deviates from mammalian Rad51•Naphthalene polysulfonated compounds (NPS) block RecA ATPase and SOS response•Selected NPS bind recombinant RecA protein withKdvalues in micromolar range•Tyr103 is an amino acid residue critical to RecA-NPS interactionsBiochemistry; Microbiology; Molecular Microbiology
