Linked Life Data

9613574

Source:http://linkedlifedata.com/resource/pubmed/id/9613574

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1998-6-18
pubmed:databankReference
pubmed:abstractText
The enzyme O6-methylguanine-DNA methyltransferase (MGMT) is the most common form of cellular defense against the biological effects of O6-methylguanine (O6-MeG) in DNA. Based on PCR amplification using primers derived from conserved amino acid sequences of MGMTs from 11 species, we isolated the DNA region coding for MGMT from the hyperthermophilic archaeon Pyrococcus sp. KOD1. The MGMT gene from KOD1 (mgtk) comprises 522 nucleotides, encoding 174 amino acid residues; its product shows considerable similarity to the corresponding mammalian, yeast and bacterial enzymes, especially around putative methyl acceptor sites. Phylogenetic analysis of MGMTs showed that archaeal MGMTs were grouped with their bacterial counterparts. The location of the MGMT gene on the KOD1 chromosome was also determined. The cloned KOD1 MGMT gene was overexpressed using the T7 RNA polymerase expression system, and the recombinant protein was purified by ammonium sulfate fractionation, heat treatment, ion-exchange chromatography and gel filtration chromatography. The purified recombinant protein was assayed for its enzyme activity by monitoring transfer of [3H]methyl groups from the substrate DNA to the MGMT protein; the activity was found to be stable at 90 degrees C for at least 30 min. When the mgtk gene was placed under the control of the lac promoter and expressed in the methyltransferase-deficient Escherichia coli strain KT233 (delta ada, delta ogt) cells, a MGMT was produced. The enzyme was functional in vivo and complemented the mutant phenotype, making the cells resistant to the cytotoxic properties of the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0026-8925
pubmed:author
pubmed:issnType
Print
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
69-77
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
The O6-methylguanine-DNA methyltransferase from the hyperthermophilic archaeon Pyrococcus sp. KOD1: a thermostable repair enzyme.
pubmed:affiliation
Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan.
pubmed:publicationType
Journal Article