Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1985-12-5
pubmed:abstractText
We have studied the structure adopted by an (A-T)34 sequence from a Xenopus globin gene when present in a negatively supercoiled plasmid. A variety of enzyme and chemical probing experiments and electrophoretic migration shift methods reveal that the sequence adopts cruciform geometry at moderate levels of supercoiling. The structure has the lowest free energy of formation yet observed for a cruciform, and no detectable kinetic barrier preventing rapid interconversion between extruded and unextruded conformations. Analysis of band-shift experiments reveals a twist change on cruciform formation of -5.8, slightly smaller than the -6.5 we would predict on the basis of a transition from B DNA. An attractive explanation consistent with this discrepancy is that the (A-T)34 stretch is locally underwound to about 11.7 base-pairs/helical turn at low levels of supercoiling. This calculation is made on the assumption that the cruciform junction is structurally similar to those examined previously, which is supported by the nuclease digestion results. This perturbed helical structure could be of considerable biological significance.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
185
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
461-78
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Facile cruciform formation by an (A-T)34 sequence from a Xenopus globin gene.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't