title: Involvement of a periplasmic protein kinase in DNA strand break repair and homologous recombination in Escherichia coli.
abstract: The involvement of signal transduction in the repair of radiation-induced damage to DNA has been known in eukaryotes but remains understudied in bacteria. This article for the first time demonstrates a role for the periplasmic lipoprotein (YfgL) with protein kinase activity transducing a signal for DNA strand break repair in Escherichia coli. Purified YfgL protein showed physical as well as functional interaction with pyrroloquinoline-quinone in solution and the protein kinase activity of YfgL was strongly stimulated in the presence of pyrroloquinoline-quinone. Transgenic E. coli cells producing Deinococcus radiodurans pyrroloquinoline-quinone synthase showed nearly four log cycle improvement in UVC dark survival and 10-fold increases in gamma radiation resistance as compared with untransformed cells. Pyrroloquinoline-quinone enhanced the UV resistance of E. coli through the YfgL protein and required the active recombination repair proteins. The yfgL mutant showed higher sensitivity to UVC, mitomycin C and gamma radiation as compared with wild-type cells and showed a strong impairment in homologous DNA recombination. The mutant expressing an active YfgL in trans recovered the lost phenotypes to nearly wild-type levels. The results strongly suggest that the periplasmic phosphoquinolipoprotein kinase YfgL plays an important role in radiation-induced DNA strand break repair and homologous recombination in E. coli.
authors.affiliation: Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai--400085, India.
authors.forename: Nivedita P
authors.initials: NP
authors.lastname: Khairnar
authors.forename: Vidya A
authors.initials: VA
authors.lastname: Kamble
authors.forename: Suhas H
authors.initials: SH
authors.lastname: Mangoli
authors.forename: Shree K
authors.initials: SK
authors.lastname: Apte
authors.forename: Hari S
authors.initials: HS
authors.lastname: Misra
mesh_terms: D053960:DNA Breaks; D004260:DNA Repair; D034301:Deinococcus / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D045542:PQQ Cofactor / Q000378:metabolism; D033903:Periplasmic Proteins / Q000235:genetics / Q000502:physiology*; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology*; D011836:Radiation Tolerance / Q000235:genetics*; D011995:Recombination, Genetic; D014466:Ultraviolet Rays
chemical_list: D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; D033903:Periplasmic Proteins; C499985:YfgL protein, E coli; C076608:pyrroloquinoline quinone synthase complex; D045542:PQQ Cofactor; D011494:Protein Kinases