TY - JOUR
T1 - Geobacillus stearothermophilus V ubiE gene product is involved in the evolution of dimethyl telluride in Escherichia coli K-12 cultures amended with potassium tellurate but not with potassium tellurite
AU - Araya, Manuel A.
AU - Swearingen, Jerry W.
AU - Plishker, Mary F.
AU - Saavedra, Claudia P.
AU - Chasteen, Thomas G.
AU - Vásquez, Claudio C.
N1 - Funding Information:
Acknowledgements This work was supported by a Robert A. Welch departmental grant (J.W.S., M.F.P., and T.G.C.) and by grant 1030234 from FONDECYT (Chile) to C.C.V. and by DI-CYT grants from Universidad de Santiago de Chile to C.P.S. and to C.C.V. M.A.A. was supported by a doctoral fellowship from MECESUP UCH 106 (Chile).
PY - 2004/7
Y1 - 2004/7
N2 - A 3.8-kb fragment of chromosomal DNA of Geobacillus stearothermophilus V cloned in pSP72 (p1VH) confers resistance to potassium tellurite (K 2TeO3) and to potassium tellurate (K2TeO 4) when the encoded genes are expressed in Escherichia coli K-12. The nt sequence of the cloned fragment predicts three ORFs of 780, 399, and 600 bp, whose encoded protein products exhibit about 80% similarity with the SUMT methyltransferase and the BtuR protein of Bacillus megaterium, and with the UbiE methyltransferase of Bacillus anthracis A2012, respectively. In addition, E. coli/p1VH cells evolved dimethyl telluride, which was released into the headspace gas above liquid cultures when amended with K2TeO 3 or with K2TeO4. After 48 h of growth in the presence of these compounds, a protein of about 25 kDa was found at a significantly higher level when crude extracts were analyzed by SDS-PAGE. The N-terminal amino acid (aa) sequence of this protein, obtained by Edman degradation, matched the deduced aa sequence predicted by the G. stearothermophilus V ubiE gene. This gene was amplified by PCR, subcloned in pET21b, and transformed into E. coli JM109(DE3). Interestingly, DMTe evolution occurred when these modified cells were grown in K2TeO4 - but not in K2TeO3 - amended media. These results may be indicative that the two Te oxyanions could be detoxified in the cell by different metabolic pathways.
AB - A 3.8-kb fragment of chromosomal DNA of Geobacillus stearothermophilus V cloned in pSP72 (p1VH) confers resistance to potassium tellurite (K 2TeO3) and to potassium tellurate (K2TeO 4) when the encoded genes are expressed in Escherichia coli K-12. The nt sequence of the cloned fragment predicts three ORFs of 780, 399, and 600 bp, whose encoded protein products exhibit about 80% similarity with the SUMT methyltransferase and the BtuR protein of Bacillus megaterium, and with the UbiE methyltransferase of Bacillus anthracis A2012, respectively. In addition, E. coli/p1VH cells evolved dimethyl telluride, which was released into the headspace gas above liquid cultures when amended with K2TeO 3 or with K2TeO4. After 48 h of growth in the presence of these compounds, a protein of about 25 kDa was found at a significantly higher level when crude extracts were analyzed by SDS-PAGE. The N-terminal amino acid (aa) sequence of this protein, obtained by Edman degradation, matched the deduced aa sequence predicted by the G. stearothermophilus V ubiE gene. This gene was amplified by PCR, subcloned in pET21b, and transformed into E. coli JM109(DE3). Interestingly, DMTe evolution occurred when these modified cells were grown in K2TeO4 - but not in K2TeO3 - amended media. These results may be indicative that the two Te oxyanions could be detoxified in the cell by different metabolic pathways.
KW - Dimethyl telluride
KW - Geobacillus stearothermophilus V
KW - Heterologous gene expression
KW - Tellurite resistance
KW - UbiE-like methyltransferase
UR - http://www.scopus.com/inward/record.url?scp=3943102828&partnerID=8YFLogxK
U2 - 10.1007/s00775-004-0554-z
DO - 10.1007/s00775-004-0554-z
M3 - Article
C2 - 15164269
AN - SCOPUS:3943102828
SN - 0949-8257
VL - 9
SP - 609
EP - 615
JO - Journal of Biological Inorganic Chemistry
JF - Journal of Biological Inorganic Chemistry
IS - 5
ER -