Linked Life Data

9918720

Source:http://linkedlifedata.com/resource/pubmed/id/9918720

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1999-3-18
pubmed:abstractText
DNA methyltransferases flip their target base out of the DNA helix. Here, we have investigated base flipping by wild-type EcoRV DNA methyltransferase (M.EcoRV) and five M.EcoRV variants (D193A, Y196A, S229A, W231R and Y258A). These variants bind to DNA and S-adenosylmethionine but have a severely reduced catalytic efficiency or are catalytically inactive. To measure base flipping three different assays were used, viz. analysis of the yields of photocrosslinking reactions between the enzymes and a substrate in which the target base is replaced by 5-iodouracil, analysis of the binding constants to substrates containing a mismatch base-pair at the target position and analysis of the salt dependence of specific complex formation. Our data show that the Y196A, W231R and Y258A variants are not able to stabilize a flipped target base, suggesting that the aromatic amino acid residues (Tyr196, Trp231 and Tyr258) are involved in hydrophobic interactions with the flipped base. The D193A variant behaves like wild-type M.EcoRV with respect to base flipping. The fact that this variant is catalytically inactive indicates that Asp193 has a function in chemical catalysis. The S229A variant can better flip modified bases but does not tightly lock the flipped base into the adenine-binding pocket, suggesting that Ser229 could form a contact to the flipped adenine.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-2836
pubmed:author
pubmed:copyrightInfo
Copyright 1998 Academic Press.
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
285
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1121-30
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Mutational analysis of target base flipping by the EcoRV adenine-N6 DNA methyltransferase.
pubmed:affiliation
Institut für Biochemie, Fachbereich Biologie, Heinrich-Buff-Ring 58, Giessen, 35392, Germany. Albert.Jeltsch@chemie.bio.uni-giessen.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't