The Journal of General and Applied Microbiology
Online ISSN : 1349-8037
Print ISSN : 0022-1260
ISSN-L : 0022-1260
Full Papers
Differential gene expression in response to copper in Acidithiobacillus ferrooxidans strains possessing dissimilar copper resistance
Xueling WuQi HuDongmei HouBo MiaoXueduan Liu
ジャーナル フリー

2010 年 56 巻 6 号 p. 491-498


Locus afe_0454 from Acidithiobacillus ferrooxidans (At.ferrooxidans) is annotated as related to copper resistance in The Institute for Genomic Research database. In our study, two At.ferrooxidans strains, 26# and DC, with different levels of copper ion resistance were isolated from acid mine drainages at two major copper mines in China, and their copper-resistance capacity was determined. The 26# strain had a copper-tolerance level of 0.22 mol/L, whereas the DC strain had a lower copper-tolerance level of 0.04 mol/L. The mutant 26# was generated from strain 26#, and its copper-tolerance level was 0.25 mol/L. Using real-time quantitative reverse transcription polymerase chain reaction, differential expression of the afe_0454 gene during copper ion stress of these three strains was investigated. The results showed that the expression of afe_0454 was increased under copper ion stress, indicating that the afe_0454 gene is sensitive to copper levels. Furthermore, the afe_0454 gene expression ratio varied in the different copper-resistant strains. Gene expression was highest in the highest copper-resistant strain. The deduced amino acid sequence of the afe_0454 gene was 56.87% non-polar, indicating the AFE_0454 protein was hydrophobic. Searching with the AFE_0454 protein in The Institute for Genomic Research database showed that the structure of the copper resistance protein D (CopD), which transports copper ions outside of the cell, had the highest sequence identity (46%). Bioinformatics analysis showed that the AFE_0454 protein has eight transmembrane helixes and was predicted to be localized to the plasma membrane. These results strongly suggested that the AFE_0454 protein is likely a transmembrane protein and might be directly involved in copper ion resistance.

© 2010 by The Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
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