Overexpression of a single membrane component from the Bacillus mer operon enhanced mercury resistance in an Escherichia coli host.
Overexpression of a mercuric ion binding protein, MerP, from the mercury resistance operon genes of Gram-positive bacterial strain Bacillus megaterium MB1 and from Gram-negative bacterial strain Pseudomonas aeruginosa K-62 was found to enhance the mercury resistance level of Escherichia coli host cells, even though they share only 27.3% identity. Immunoblot analysis showed that MerP (BMerP) from Bacillus could be expressed on the membrane fraction of E. coli cells. Treated with 10 microM Hg2+, a recombinant strain harboring the BMerP gene significantly improved, showing a 27% increase in mercuric ion adsorption capacity, 16% better than that of a Pseudomonas merP gene (PMerP)-harboring strain. While multiple heavy metals co-existed, the mercuric ion adsorption capacity of the BMerP-harboring E. coli was not affected while that of the PMerP-harboring strain decreased. These results suggest that BMerP can act as a bio-adsorbent compartmentalizing the toxic mercuric ion on the cell membrane and enhancing resistance.
Hsieh
Ju-Liang
JL
Department of Life Sciences, National Chung Hsing University, Taiwan, Republic of China.
Chen
Ching-Yi
CY
Chang
Jo-Shu
JS
Endo
Ginro
G
Huang
Chieh-Chen
CC
D000327:Adsorption; D001407:Bacillus / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D008628:Mercury / Q000493:pharmacokinetics*; D009876:Operon; D020011:Protective Agents; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D014161:Transduction, Genetic
D001426:Bacterial Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; C086060:MerP protein, Bacteria; D020011:Protective Agents; D011506:Proteins; D008628:Mercury