Linked Life Data

7495790

Source:http://linkedlifedata.com/resource/pubmed/id/7495790

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
48
pubmed:dateCreated
1996-1-18
pubmed:abstractText
Chemical and enzymatic probing (footprinting) of the reactivity of the promoter DNA backbone is applied to characterize two binary open complexes RPo1 (-Mg2+) and RPo2 (+Mg2+), formed by Escherichia coli RNA polymerase (E sigma 70) at the lambda PR promoter. We report that HO. detects major differences in backbone reactivity between RPo1 and RPo2 in the open region from -4 to +1 relative to the transcription start site. Deoxyribose sugars at positions -4 to +1 of the t (template) strand react with HO. in RPo2 but are relatively protected in RPo1. Binding of Mg2+ to convert RPo1 to RPo2 therefore increases the reactivity of two negatively charged footprinting agents [MnO4-; Suh, W.-C., Ross, W., & Record, M. T., Jr., (1993) Science 259, 358-361; and Fe(EDTA)2-/HO.] at the start site and is required for binding of the negatively-charged initiating nucleotides to the polymerase and the t strand at the start site. We propose that these effects result from binding of two Mg2+ ions to the catalytic carboxyls in the nucleotide binding sites. Except for the key region on the t strand at the start site, the promoter DNA of both RPo1 and RPo2 is continuously protected from DNase I and hydroxyl radical (HO.) cleavage between the -12 and +25 promoter positions. Protection in the upstream region, extending from -13 to about -70, is periodic, with an 11 base pair periodicity indicative of binding of polymerase to a single face of the DNA helix.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15624-32
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
HO. and DNase I probing of E sigma 70 RNA polymerase--lambda PR promoter open complexes: Mg2+ binding and its structural consequences at the transcription start site.
pubmed:affiliation
Department of Biochemistry, University of Wisconsin--Madison 53706, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.