Bacillus subtilis RadA/Sms contributes to chromosomal transformation and DNA repair in concert with RecA and circumvents replicative stress in concert with DisA

Torres, R., Serrano, E. , Tramm, K. and Alonso, J. C. (2019) Bacillus subtilis RadA/Sms contributes to chromosomal transformation and DNA repair in concert with RecA and circumvents replicative stress in concert with DisA. DNA Repair, 77, pp. 45-57. (doi: 10.1016/j.dnarep.2019.03.002) (PMID:30877841)

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Abstract

Bacillus subtilis radA is epistatic to disA and recA genes in response to methyl methane sulfonate- and 4-nitroquinoline-1-oxide-induced DNA damage. We show that ΔradA cells were sensitive to mitomycin C- and H2O2-induced damage and impaired in natural chromosomal transformation, whereas cells lacking DisA were not. RadA/Sms mutants in the conserved H1 (K104A and K104R) or KNRFG (K255A and K255R) motifs fail to rescue the sensitivity of ΔradA in response to the four different DNA damaging agents. A RadA/Sms H1 or KNRFG mutation impairs both chromosomal and plasmid transformation, but the latter defect was suppressed by inactivating RecA. RadA/Sms K255A, K255R and wild type RadA/Sms reduced the diadenylate cyclase activity of DisA, whereas RadA/Sms K104A and K104R blocked it. Single-stranded and Holliday junction DNA are preferentially bound over double-stranded DNA by RadA/Sms and its variants. Moreover, RadA/Sms ATPase activity was neither stimulated by a variety of DNA substrates nor by DisA. RadA/Sms possesses a 5´→3´ DNA helicase activity. The RadA/Sms mutants neither hydrolyze ATP nor unwind DNA. Thus, we propose that RadA/Sms has two activities: to modulate DisA and to promote RecA-mediated DNA strand exchange. Both activities are required to coordinate responses to replicative stress and genetic recombination.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Serrano, Dr Ester
Authors: Torres, R., Serrano, E., Tramm, K., and Alonso, J. C.
College/School:College of Medical Veterinary and Life Sciences > School of Infection & Immunity
Journal Name:DNA Repair
Publisher:Elsevier
ISSN:1568-7864
ISSN (Online):1568-7856
Published Online:04 March 2019

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