Linked Life Data

12527298

Source:http://linkedlifedata.com/resource/pubmed/id/12527298

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2003-1-15
pubmed:abstractText
The Escherichia coli UvrD protein (helicase II) is an SF1 superfamily helicase required for methyl-directed mismatch repair and nucleotide excision repair of DNA. We have characterized quantitatively the self-assembly equilibria of the UvrD protein as a function of [NaCl], [glycerol], and temperature (5-35 degrees C; pH 8.3) using analytical sedimentation velocity and equilibrium techniques, and find that UvrD self-associates into dimeric and tetrameric species over a range of solution conditions (t</=25 degrees C). Increasing [NaCl] from 20mM to 200 mM decreases the dimerization equilibrium constant (L(20)) from 2.33(+/-0.30) microM(-1) to 0.297(+/-0.006) microM(-1) (pH 8.3, 20% (v/v) glycerol, 25 degrees C). The overall tetramerization equilibrium constant (L(40)) is 5.11(+/-0.80) microM(-3) at 20mM NaCl, but decreases so that it is not measurable at 200 mM NaCl. At 500 mM NaCl, only UvrD monomers are detectable. Increasing [glycerol] over the range from 20% to 40% (v/v) decreases both L(20) and L(40). We find no evidence for hexamer formation, although a species consistent in size with an octamer is detected at 35 degrees C. Inclusion of either ADP or ATPgammaS does not affect either L(20) or L(40) significantly, and does not induce the formation of additional assembly states. We also investigated the stoichiometry of UvrD binding to a 3'-(dT)(20)-18 bp DNA substrate by sedimentation equilibrium. At saturating concentrations of UvrD, three UvrD monomers can bind to the DNA substrate, although only two UvrD monomers are required to form a processive helicase complex. When the total DNA substrate concentration is about twofold greater than the total UvrD concentration, the vast majority of the DNA is bound by a single UvrD monomer.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
31
pubmed:volume
325
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
889-912
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Self-association equilibria of Escherichia coli UvrD helicase studied by analytical ultracentrifugation.
pubmed:affiliation
Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Avenue, Box 8231, St. Louis, MO 63110-1093, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.