title: Identification of a chemical that inhibits the mycobacterial UvrABC complex in nucleotide excision repair.
abstract: Bacterial DNA can be damaged by reactive nitrogen and oxygen intermediates (RNI and ROI) generated by host immunity, as well as by antibiotics that trigger bacterial production of ROI. Thus a pathogen's ability to repair its DNA may be important for persistent infection. A prominent role for nucleotide excision repair (NER) in disease caused by Mycobacterium tuberculosis (Mtb) was suggested by attenuation of uvrB-deficient Mtb in mice. However, it was unknown if Mtb's Uvr proteins could execute NER. Here we report that recombinant UvrA, UvrB, and UvrC from Mtb collectively bound and cleaved plasmid DNA exposed to ultraviolet (UV) irradiation or peroxynitrite. We used the DNA incision assay to test the mechanism of action of compounds identified in a high-throughput screen for their ability to delay recovery of M. smegmatis from UV irradiation. 2-(5-Amino-1,3,4-thiadiazol-2-ylbenzo[f]chromen-3-one) (ATBC) but not several closely related compounds inhibited cleavage of damaged DNA by UvrA, UvrB, and UvrC without intercalating in DNA and impaired recovery of M. smegmatis from UV irradiation. ATBC did not affect bacterial growth in the absence of UV exposure, nor did it exacerbate the growth defect of UV-irradiated mycobacteria that lacked uvrB. Thus, ATBC appears to be a cell-penetrant, selective inhibitor of mycobacterial NER. Chemical inhibitors of NER may facilitate studies of the role of NER in prokaryotic pathobiology.
authors.affiliation: Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10065, USA.
authors.forename: Nayef
authors.initials: N
authors.lastname: Mazloum
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Stegman
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Croteau
authors.forename: Bennett
authors.initials: B
authors.lastname: Van Houten
authors.forename: Nyoun Soo
authors.initials: NS
authors.lastname: Kwon
authors.forename: Yan
authors.initials: Y
authors.lastname: Ling
authors.forename: Caitlyn
authors.initials: C
authors.lastname: Dickinson
authors.forename: Aditya
authors.initials: A
authors.lastname: Venugopal
authors.forename: Mohammad Atif
authors.initials: MA
authors.lastname: Towheed
authors.forename: Carl
authors.initials: C
authors.lastname: Nathan
mesh_terms: D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects* / Q000528:radiation effects; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004706:Endodeoxyribonucleases / Q000037:antagonists & inhibitors* / Q000172:deficiency / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D020102:Mycobacterium smegmatis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D030421:Peroxynitrous Acid / Q000494:pharmacology; D013830:Thiadiazoles / Q000737:chemistry / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D013830:Thiadiazoles; D030421:Peroxynitrous Acid; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC