Linked Life Data

10671528

Source:http://linkedlifedata.com/resource/pubmed/id/10671528

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2000-3-21
pubmed:abstractText
Pre-steady state partitioning analysis of the HhaI DNA methyltransferase directly demonstrates the catalytic competence of the enzyme.DNA complex and the lack of catalytic competence of the enzyme.S-adenosyl-L-methionine (AdoMet) complex. The enzyme.AdoMet complex does form, albeit with a 50-fold decrease in affinity compared with the ternary enzyme.AdoMet.DNA complex. These findings reconcile the distinct binding orientations previously observed within the binary enzyme.AdoMet and ternary enzyme. S-adenosyl-L-homocysteine.DNA crystal structures. The affinity of the enzyme for DNA is increased 900-fold in the presence of its cofactor, and the preference for hemimethylated DNA is increased to 12-fold over unmethylated DNA. We suggest that this preference is partially due to the energetic cost of retaining a cavity in place of the 5-methyl moiety in the ternary complex with the unmethylated DNA, as revealed by the corresponding crystal structures. The hemi- and unmethylated substrates alter the fates and lifetimes of discrete enzyme.substrate intermediates during the catalytic cycle. Hemimethylated substrates partition toward product formation versus dissociation significantly more than unmethylated substrates. The mammalian DNA cytosine-C-5 methyltransferase Dnmt1 shows an even more pronounced partitioning toward product formation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4912-9
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Reconciling structure and function in HhaI DNA cytosine-C-5 methyltransferase.
pubmed:affiliation
Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.