DNA replication defects in a mutant deficient in the thioredoxin homolog YbbN

Hai Tuong Le, Valérie Gautier, Fatoum Kthiri, Masamichi Kohiyama, Tsutomu Katayama, Gilbert Richarme

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Abstract

Escherichia coli contains two thioredoxins, Trx1 and Trx2, and a thioredoxin-like protein, YbbN, that displays both redox and chaperone properties. Since three out of the six proteins of the YbbN interactome (Butland et al., 2005) are components of DNA polymerase 3 holoenzyme (i.e. the β-clamp DnaN, the θ subunit HolE and the δ' subunit HolB), we investigated whether the ybbN mutant presents DNA replication defects. We found that this mutant incorporates 3H-thymidine at higher rates than the parental strain and displays overinitiation, hypermutator and filamentation phenotypes with the occurrence of anucleated cells. Moreover, YbbN functions as a bona fide chaperone in the refolding of the urea-unfolded β-clamp. These results suggest that the DNA replication and cell division defects of the ybbN mutant might best be explained by chaperone functions of YbbN in the biogenesis of DNA polymerase 3 holoenzyme.

Original languageEnglish
Pages (from-to)52-57
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume405
Issue number1
DOIs
Publication statusPublished - Feb 4 2011

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All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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