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Publication Abstract from PubMed

Antimicrobial resistance threatens the eradication of infectious diseases and impairs the efficacy of available therapeutics. The bacterial SOS pathway is a conserved response triggered by genotoxic stresses and represents one of the principal mechanisms that lead to resistance. The RecA recombinase acts as a DNA-damage sensor inducing the autoproteolysis of the transcriptional repressor LexA, thereby derepressing SOS genes that mediate DNA repair, survival to chemotherapy, and hypermutation. The inhibition of such pathway represents a promising strategy for delaying the evolution of antimicrobial resistance. We report the identification, via llama immunization and phage display, of nanobodies that bind LexA with sub-micromolar affinity and block autoproteolysis, repressing SOS response in Escherichia coli. Biophysical characterization of nanobody-LexA complexes revealed that they act by trapping LexA in an inactive conformation and interfering with RecA engagement. Our studies pave the way to the development of new-generation antibiotic adjuvants for the treatment of bacterial infections.

Nanobodies targeting LexA autocleavage disclose a novel suppression strategy of SOS-response pathway.,Maso L, Vascon F, Chinellato M, Goormaghtigh F, Bellio P, Campagnaro E, Van Melderen L, Ruzzene M, Pardon E, Angelini A, Celenza G, Steyaert J, Tondi D, Cendron L Structure. 2022 Oct 6. pii: S0969-2126(22)00357-4. doi:, 10.1016/j.str.2022.09.004. PMID:36240773^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.