TY - JOUR
T1 - A role of ygfZ in the Escherichia coli response to plumbagin challenge
AU - Lin, Ching Nan
AU - Syu, Wan Jr
AU - Sun, Wei Sheng W.
AU - Chen, Jenn Wei
AU - Chen, Tai Hung
AU - Don, Ming Jaw
AU - Wang, Shao Hung
N1 - Funding Information:
The technical support from Yang-Ming Proteomic Center is acknowledged. We also thank Dr. CS Chen from Ohio State University (USA) for the useful discussion and Dr. R Kirby for critical reading of this manuscript. This work was supported in part by a grant from Ministry of Education, Aim for the Top University Plan http://english.moe.gov.tw/. WJS was supported by grants 97-2627-M-010-003 and 97-2320-B-010-005-MY3 from the National Science Council. SHW was supported by 98-2320-B-415-004-MY3 from the National Science Council, Taiwan. Hereby, we claim that this is an independent study and has no connection to the recent report by Waller et al., (Proc Natl Acad Sci USA 2010).
PY - 2010
Y1 - 2010
N2 - Plumbagin is found in many herbal plants and inhibits the growth of various bacteria. Escherichia coli strains are relatively resistant to this drug. The mechanism of resistance is not clear. Previous findings showed that plumbagin treatment triggered up-regulation of many genes in E. coli including ahpC, mdaB, nfnB, nfo, sodA, yggX and ygfZ. By analyzing minimal inhibition concentration and inhibition zones of plumbagin in various gene-disruption mutants, ygfZ and sodA were found critical for the bacteria to resist plumbagin toxicity. We also found that the roles of YgfZ and SodA in detoxifying plumbagin are independent of each other. This is because of the fact that ectopically expressed SodA reduced the superoxide stress but not restore the resistance of bacteria when encountering plumbagin at the absence of ygfZ. On the other hand, an ectopically expressed YgfZ was unable to complement and failed to rescue the plumbagin resistance when sodA was perturbed. Furthermore, mutagenesis analysis showed that residue Cys228 within YgfZ fingerprint region was critical for the resistance of E. coli to plumbagin. By solvent extraction and HPLC analysis to follow the fate of the chemical, it was found that plumbagin vanished apparently from the culture of YgfZ-expressing E. coli. A less toxic form, methylated plumbagin, which may represent one of the YgfZ-dependent metabolites, was found in the culture supernatant of the wild type E. coli but not in the ygfZ mutant. Our results showed that the presence of ygfZ is not only critical for the E coli resistance to plumbagin but also facilitates the plumbagin degradation.
AB - Plumbagin is found in many herbal plants and inhibits the growth of various bacteria. Escherichia coli strains are relatively resistant to this drug. The mechanism of resistance is not clear. Previous findings showed that plumbagin treatment triggered up-regulation of many genes in E. coli including ahpC, mdaB, nfnB, nfo, sodA, yggX and ygfZ. By analyzing minimal inhibition concentration and inhibition zones of plumbagin in various gene-disruption mutants, ygfZ and sodA were found critical for the bacteria to resist plumbagin toxicity. We also found that the roles of YgfZ and SodA in detoxifying plumbagin are independent of each other. This is because of the fact that ectopically expressed SodA reduced the superoxide stress but not restore the resistance of bacteria when encountering plumbagin at the absence of ygfZ. On the other hand, an ectopically expressed YgfZ was unable to complement and failed to rescue the plumbagin resistance when sodA was perturbed. Furthermore, mutagenesis analysis showed that residue Cys228 within YgfZ fingerprint region was critical for the resistance of E. coli to plumbagin. By solvent extraction and HPLC analysis to follow the fate of the chemical, it was found that plumbagin vanished apparently from the culture of YgfZ-expressing E. coli. A less toxic form, methylated plumbagin, which may represent one of the YgfZ-dependent metabolites, was found in the culture supernatant of the wild type E. coli but not in the ygfZ mutant. Our results showed that the presence of ygfZ is not only critical for the E coli resistance to plumbagin but also facilitates the plumbagin degradation.
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U2 - 10.1186/1423-0127-17-84
DO - 10.1186/1423-0127-17-84
M3 - Article
C2 - 21059273
AN - SCOPUS:78049488541
SN - 1021-7770
VL - 17
JO - Journal of biomedical science
JF - Journal of biomedical science
IS - 1
M1 - 84
ER -