Linked Life Data

2719955

Source:http://linkedlifedata.com/resource/pubmed/id/2719955

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1989-6-29
pubmed:abstractText
The MerR protein from the Tn501 mercury resistance operon is a metalloregulatory transcriptional switch, converting from repressor to activator on binding of Hg(II). We have determined via binding studies with 203Hg(II) that a single Hg(II) atom binds to the MerR dimer (32 kDa) with a half-saturation concentration of 10(-7) M in the presence of up to 10(-3) M exogenous thiols. This 10(4) selective binding is specific for the binding of Hg(II) and corresponds to concentrations of metal that induce mercury(II) resistance in vivo. Kd values for MerR binding, in the absence and presence of Hg(II), to a 305 bp DNA fragment containing the 18 bp dyad symmetry element, DS1, located at -35 to -10 upstream of the mer structural genes, were determined by a gel shift assay. A Kd of 10(-10) M for free MerR and 10(-11) M for Hg(II)-MerR complexes was revealed. Measurements of koff values, by this assay, show equally long-lived complexes of MerR-DNA (51-min half-life) and Hg(II)-MerR-DNA (49-min half-life), suggesting that Hg(II) accelerates MerR binding to DNA rather than influencing the dissociation rate of the protein-DNA complex. In contrast, 203Hg(II) studies reveal that mercuric ions rapidly dissociate and associate with MerR-DNA complexes. Extensive footprinting studies by DNase I, methylation protection, and hydroxyl radicals indicate MerR stays bound to DS1 even on addition of Hg(II) and shares no interaction in vitro with a second dyad symmetry element, DS2, centered at -79/-80.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
28
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2331-9
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:2719955-Alkylation, pubmed-meshheading:2719955-Bacterial Proteins, pubmed-meshheading:2719955-Base Sequence, pubmed-meshheading:2719955-Chromatography, High Pressure Liquid, pubmed-meshheading:2719955-Cysteine, pubmed-meshheading:2719955-DNA, Bacterial, pubmed-meshheading:2719955-DNA-Binding Proteins, pubmed-meshheading:2719955-Deoxyribonuclease I, pubmed-meshheading:2719955-Dithionitrobenzoic Acid, pubmed-meshheading:2719955-Gene Expression Regulation, pubmed-meshheading:2719955-Iodoacetamide, pubmed-meshheading:2719955-Kinetics, pubmed-meshheading:2719955-Ligands, pubmed-meshheading:2719955-Mercury, pubmed-meshheading:2719955-Metalloproteins, pubmed-meshheading:2719955-Methylation, pubmed-meshheading:2719955-Mutation, pubmed-meshheading:2719955-Operator Regions, Genetic, pubmed-meshheading:2719955-Promoter Regions, Genetic, pubmed-meshheading:2719955-Protein Binding, pubmed-meshheading:2719955-Thermodynamics, pubmed-meshheading:2719955-Transcription, Genetic
pubmed:year
1989
pubmed:articleTitle
Transcriptional switching by the metalloregulatory MerR protein: initial characterization of DNA and mercury (II) binding activities.
pubmed:affiliation
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.