Linked Life Data

12879741

Source:http://linkedlifedata.com/resource/pubmed/id/12879741

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-7-25
pubmed:abstractText
We purified and characterized both the methyltransferase and the endonuclease containing the HsdS delta 50 subunit (type I restriction endonucleases are composed of three subunits--HsdR required for restriction, HsdM required for methylation and HsdS responsible for DNA recognition) produced from the deletion mutation hsdS delta 50 of the type IC R-M system EcoR 124I; this mutant subunit lacks the C-terminal 163 residues of HsdS and produces a novel DNA specificity. Analysis of the purified HsDs delta 50 subunit indicated that during purification it is subject to partial proteolysis resulting in removal of approximately 1 kDa of the polypeptide at the C-terminus. This proteolysis prevented the purification of further deletion mutants, which were determined as having a novel DNA specificity in vivo. After biochemical characterization of the mutant DNA methyltransferase (MTase) and restriction endonuclease we found only one difference comparing with the wild-type enzyme--a significantly higher binding affinity of the MTase for the two substrates of hemimethylated and fully methylated DNA. This indicates that MTase delta 50 is less able to discriminate the methylation status of the DNA during its binding. However, the mutant MTase still preferred hemimethylated DNA as the substrate for methylation. We fused the hsdM and hsdS delta 50 genes and showed that the HsdM-HsdS delta 50 fusion protein is capable of dimerization confirming the model for assembly of this deletion mutant.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins, http://linkedlifedata.com/resource/pubmed/chemical/DNA, http://linkedlifedata.com/resource/pubmed/chemical/DNA Restriction-Modification Enzymes, http://linkedlifedata.com/resource/pubmed/chemical/DNA-Binding Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Deoxyribonucleases, Type I..., http://linkedlifedata.com/resource/pubmed/chemical/Escherichia coli Proteins, http://linkedlifedata.com/resource/pubmed/chemical/HSDS protein, Bacteria, http://linkedlifedata.com/resource/pubmed/chemical/HsdM protein, Bacteria, http://linkedlifedata.com/resource/pubmed/chemical/HsdR protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Proteins, http://linkedlifedata.com/resource/pubmed/chemical/endodeoxyribonuclease EcoR124I
pubmed:status
MEDLINE
pubmed:issn
0015-5632
pubmed:author
pubmed:issnType
Print
pubmed:volume
48
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
319-28
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Characterization of an EcoR124I restriction-modification enzyme produced from a deleted form of the DNA-binding subunit, which results in a novel DNA specificity.
pubmed:affiliation
Biophysics Laboratories, School of Biological Sciences, University of Portsmouth, Portsmouth, PO1 2DT, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't