Crystal structure of E.coli LexA in complex with nanobody NbSOS1(Nb14497)Crystal structure of E.coli LexA in complex with nanobody NbSOS1(Nb14497)

Structural highlights

7zra is a 8 chain structure with sequence from Escherichia coli and Lama glama. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.8Å
Ligands:
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

C3SHL2_ECOLX Represses a number of genes involved in the response to DNA damage (SOS response), including recA and lexA. Binds to the 16 bp palindromic sequence 5'-CTGTATATATATACAG-3'. In the presence of single-stranded DNA, RecA interacts with LexA causing an autocatalytic cleavage which disrupts the DNA-binding part of LexA, leading to derepression of the SOS regulon and eventually DNA repair.[HAMAP-Rule:MF_00015]

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 Nov 3;30(11):1479-1493.e9. doi: 10.1016/j.str.2022.09.004. Epub , 2022 Oct 13. PMID:36240773[1]

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

References

  1. 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. Nanobodies targeting LexA autocleavage disclose a novel suppression strategy of SOS-response pathway. Structure. 2022 Oct 6. pii: S0969-2126(22)00357-4. doi:, 10.1016/j.str.2022.09.004. PMID:36240773 doi:http://dx.doi.org/10.1016/j.str.2022.09.004

7zra, resolution 2.80Å

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