Structure and function of Tn5467, a Tn21-like transposon located on the Thiobacillus ferrooxidans broad-host-range plasmid pTF-FC2.
A 3.5-kb region of plasmid pTF-FC2, which contains a transposon-like element designated Tn5467, has been sequenced, and its biological activity has been investigated. The transposon is bordered by two 38-bp inverted repeat sequences which have sequence identity in 37 of 38 and in 38 of 39 bp to the tnpA distal and tnpA proximal inverted repeats of Tn21, respectively. Within these borders, open reading frames with amino acid similarity to a glutaredoxin-like protein, a MerR regulatory protein, and a multidrug-resistant-membrane transport-like protein were found. The gene for the glutaredoxin-like protein was expressed in Escherichia coli and enabled growth of a glutathione-requiring E. coli trxA gshA mutant on minimal medium and the reduction of methionine sulfoxide to methionine. In addition, there were two regions which, when translated, had homology to 85% of the N-terminal region of the Tn21 resolvase (tnpR) and to 15% of the C terminus of the Tn21 transposase (tnpA). A region containing res-like sites was located immediately upstream of the partial tnpR gene. Neither the partial transposase nor the resolvase genes of Tn5467 were biologically active, but Tn5467 was transposed and resolved when the Tn21 transposase and resolvase were provided in trans. Tn5467 appears to be a defective transposon which belongs to the Tn21 subgroup of the Tn3 family.
Department of Microbiology, University of Cape Town, Rondebosch, South Africa.
A M
AM
Clennel
B
B
Johnston
D E
DE
Rawlings
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013855:Thiobacillus / Q000235:genetics*; D045564:Transposon Resolvases
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; C051124:MerR protein, Bacteria; C473490:Tn21 resolvase; D045564:Transposon Resolvases