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Involvement of a periplasmic protein kinase in DNA strand break repair and homologous recombination in Escherichia coli
Author(s) -
Khairnar Nivedita P.,
Kamble Vidya A.,
Mangoli Suhas H.,
Apte Shree K.,
Misra Hari S.
Publication year - 2007
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2007.05779.x
Subject(s) - biology , periplasmic space , deinococcus radiodurans , homologous recombination , dna repair , pyrroloquinoline quinone , mutant , dna pkcs , microbiology and biotechnology , non homologous end joining , escherichia coli , dna , biochemistry , gene , enzyme , cofactor
Summary 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 .