Linked Life Data

11859082

Source:http://linkedlifedata.com/resource/pubmed/id/11859082

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2002-4-29
pubmed:abstractText
The DNA repair enzyme uracil DNA glycosylase (UDG) hydrolyzes the glycosidic bond of deoxyuridine in DNA by a remarkable mechanism involving formation of a positively charged oxacarbenium ion-uracil anion intermediate. We have proposed that the positively charged intermediate is stabilized by being sandwiched between the combined negative charges of the anionic uracil leaving group and a conserved aspartate residue that are located on opposite faces of the sugar ring. Here we establish that a duplex DNA oligonucleotide containing a cationic 1-aza-deoxyribose (I) oxacarbenium ion mimic is a potent inhibitor of UDG that binds tightly to the enzyme-uracil anion (EU(-)) product complex (K(D) of EU(-) = 110 pm). The tight binding of I to the EU(-) complex results from its extremely slow off rate (k(off) = 0.0008 s(-1)), which is 25,000-fold slower than substrate analogue DNA. Removal of Asp(64) and His(187), which are involved in stabilization of the cationic sugar and the anionic uracil leaving group, respectively, specifically weakens binding of I to the UDG-uracil complex by 154,000-fold, without significantly affecting substrate or product binding. These results suggest that electrostatic effects can effectively stabilize such an intermediate by at least -7 kcal/mol, without leading to anticatalytic stabilization of the substrate and products.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15385-92
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Probing the limits of electrostatic catalysis by uracil DNA glycosylase using transition state mimicry and mutagenesis.
pubmed:affiliation
Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2185, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.