Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1997-5-23
pubmed:abstractText
The Escherichia coli soxRS regulon activates oxidative stress and antibiotic resistance genes in two transcriptional stages. SoxR protein becomes activated in cells exposed to excess superoxide or nitric oxide and then stimulates transcription of the soxS gene, whose product in turn activates>/=10 regulon promoters. Purified SoxR protein is a homodimer containing a pair of [2Fe-2S] centers essential for soxS transcription in vitro . The [2Fe-2S] centers are thought to be anchored by a C-terminal cluster of four cysteine residues in SoxR. Here we analyze mutant SoxR derivatives with individual cysteines replaced by alanine residues (Cys-->Ala). The mutant proteins in cell-free extracts bound the soxS promoter with wild-type affinity, but upon purification lacked Fe or detectable transcriptional activity for soxS in vitro . Electron paramagnetic resonance measurements in vivo indicated that the Cys-->Ala proteins lacked the [2Fe-2S] centers seen for wild-type SoxR. The Cys-->Ala mutant proteins failed to activate soxS expression in vivo in response to paraquat, a superoxide- generating agent. However, when expressed to approximately 5% of the cell protein, the Cys-->Ala derivatives increased basal soxS transcription 2-4-fold. Overexpression of the Cys119-->Ala mutant protein strongly interfered with soxS activation by wild-type SoxR in response to paraquat. These studies demonstrate the essential role of the [2Fe-2S] centers for SoxR activation in vivo ; the data may also indicate oxidant-independent mechanisms of transcriptional activation by SoxR.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-1317841, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-1400156, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-1653416, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-1695893, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-1696718, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-5432063, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-7532626, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-7592901, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-7670195, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-7673113, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-7679383, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-7730338, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-7896685, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8226698, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8234347, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8282690, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8306957, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8391920, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8449900, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8522515, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8626315, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8631739, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8790350, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8809747, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8816757, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8821940, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-8969171, http://linkedlifedata.com/resource/pubmed/commentcorrection/9092651-9019397
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0305-1048
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1469-75
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Cysteine-to-alanine replacements in the Escherichia coli SoxR protein and the role of the [2Fe-2S] centers in transcriptional activation.
pubmed:affiliation
Department of Molecular and Cellular Toxicology, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't