Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1999-7-15
pubmed:abstractText
In contrast to many type II restriction enzymes, dimeric proteins that cleave DNA at individual recognition sites 4-6 bp long, the SfiI endonuclease is a tetrameric protein that binds to two copies of an elongated sequence before cutting the DNA at both sites. The mode of action of the SfiI endonuclease thus seems more appropriate for DNA rearrangements than for restriction. To elucidate its biological function, strains of Escherichia coli expressing the SfiI restriction-modification system were transformed with plasmids carrying SfiI sites. The SfiI system often failed to restrict the survival of a plasmid with one SfiI site, but plasmids with two or more sites were restricted efficiently. Plasmids containing methylated SfI sites were not restricted. No rearrangements of the plasmids carrying SfiI sites were detected among the transformants. Hence, provided the target DNA contains at least two recognition sites, SfiI displays all of the hallmarks of a restriction-modification system as opposed to a recombination system in E. coli cells. The properties of the system in vivo match those of the enzyme in vitro. For both restriction in vivo and DNA cleavage in vitro, SfiI operates best with two recognition sites on the same DNA.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1243-54
pubmed:dateRevised
2009-9-29
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
DNA restriction dependent on two recognition sites: activities of the SfiI restriction-modification system in Escherichia coli.
pubmed:affiliation
Department of Biochemistry, School of Medical Sciences, University of Bristol, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't