title: UvrD2 is essential in Mycobacterium tuberculosis, but its helicase activity is not required.
abstract: UvrD is an SF1 family helicase involved in DNA repair that is widely conserved in bacteria. Mycobacterium tuberculosis has two annotated UvrD homologues; here we investigate the role of UvrD2. The uvrD2 gene at its native locus could be knocked out only in the presence of a second copy of the gene, demonstrating that uvrD2 is essential. Analysis of the putative protein domain structure of UvrD2 shows a distinctive domain architecture, with an extended C terminus containing an HRDC domain normally found in SF2 family helicases and a linking domain carrying a tetracysteine motif. Truncated constructs lacking the C-terminal domains of UvrD2 were able to compensate for the loss of the chromosomal copy, showing that these C-terminal domains are not essential. Although UvrD2 is a functional helicase, a mutant form of the protein lacking helicase activity was able to permit deletion of uvrD2 at its native locus. However, a mutant protein unable to hydrolyze ATP or translocate along DNA was not able to compensate for lack of the wild-type protein. Therefore, we concluded that the essential role played by UvrD2 is unlikely to involve its DNA unwinding activity and is more likely to involve DNA translocation and, possibly, protein displacement.
authors: MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK. alan.williams@nimr.mrc.ac.uk
authors: Alan
authors: A
authors: Williams
authors: Carolin
authors: C
authors: Güthlein
authors: Nicola
authors: N
authors: Beresford
authors: Erik C
authors: EC
authors: Böttger
authors: Burkhard
authors: B
authors: Springer
authors: Elaine O
authors: EO
authors: Davis
mesh_terms: D000251:Adenosine Triphosphatases; D000255:Adenosine Triphosphate / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002876:Chromosomes, Bacterial / Q000235:genetics; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development; D017353:Gene Deletion; D005798:Genes, Bacterial; D020043:Genes, Essential; D056426:Genetic Loci; D006868:Hydrolysis; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics; D010957:Plasmids; D017434:Protein Structure, Tertiary; D014178:Translocation, Genetic
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D004265:DNA Helicases