Linked Life Data

10930409

Source:http://linkedlifedata.com/resource/pubmed/id/10930409

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
42
pubmed:dateCreated
2000-11-20
pubmed:abstractText
The human protein MED1 (also known as MBD4) was previously isolated in a two-hybrid screening using the mismatch repair protein MLH1 as a bait, and shown to have homology to bacterial base excision repair DNA N-glycosylases/lyases. To define the mechanisms of action of MED1, we implemented a sensitive glycosylase assay amenable to kinetic analysis. We show that MED1 functions as a mismatch-specific DNA N-glycosylase active on thymine, uracil, and 5-fluorouracil when these bases are opposite to guanine. MED1 lacks uracil glycosylase activity on single-strand DNA and abasic site lyase activity. The glycosylase activity of MED1 prefers substrates containing a G:T mismatch within methylated or unmethylated CpG sites; since G:T mismatches can originate via deamination of 5-methylcytosine to thymine, MED1 may act as a caretaker of genomic fidelity at CpG sites. A kinetic analysis revealed that MED1 displays a fast first cleavage reaction followed by slower subsequent reactions, resulting in biphasic time course; this is due to the tight binding of MED1 to the abasic site reaction product rather than a consequence of enzyme inactivation. Comparison of kinetic profiles revealed that the MED1 5-methylcytosine binding domain and methylation of the mismatched CpG site are not required for efficient catalysis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
32422-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Biphasic kinetics of the human DNA repair protein MED1 (MBD4), a mismatch-specific DNA N-glycosylase.
pubmed:affiliation
Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't