Tn5044-conferred mercury resistance depends on temperature: the complexity of the character of thermosensitivity |
| |
Authors: | Kholodii Gennady Bogdanova Elena |
| |
Institution: | (1) Institute of Molecular Genetics, Russian Academy of Sciences, 123182 Moscow, Russia (Phone |
| |
Abstract: | Escherichia coli K12 containing the transposon Tn5044 mer operon (merR, T, P, C, and A genes) is resistant to mercuric chloride at 30°C but sensitive to this compound at 37–41.5°C. We have studied the mechanism underlying the temperature-sensitive nature of this mercury resistance phenotype, and found that the expression of the Tn5044 merA gene coding for mercuric reductase (MerA) is severely inhibited at non-permissive temperatures. Additionally, MerA showed a considerably reduced functional activity in vivo at non-permissive temperatures. However, the temperature-sensitive character of the functioning of this enzyme in cell extracts, where it interacted with one of the low-molecular weight SH compounds rather than with the transport protein MerT (as is the case in vivo), was not apparent. These data suggest that the temperature-sensitive mercury resistance phenotype should stay under control at two stages: when the merA gene is expressed and when its product interacts with MerT to accept the mercuric ion. |
| |
Keywords: | Hg(II) uptake system MerA mercuric reductase mer operon MerP MerT SH compound Tn5041 Tn5044 transport protein transposon |
本文献已被 PubMed SpringerLink 等数据库收录! |
|