Linked Life Data

18491920

Source:http://linkedlifedata.com/resource/pubmed/id/18491920

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
2008-6-10
pubmed:abstractText
The DNA binding domain of the yeast transcription factor Mbp1 is a winged helix-turn-helix structure, with an extended DNA binding site involving C-terminal "tail" residues. The thermodynamics of the interaction of the DNA binding domain with its target DNA sequence have been determined using fluorescence anisotropy and calorimetry. The dissociation constant was determined as a function of pH and ionic strength in assessing the relative importance of specific and nonspecific ionic interactions. Mutational analysis of the residues in the binding site was used to determine their contributions to binding. The three tail histidine residues and His 63 in the recognition helix accounted for most of the pH dependence of the DNA binding. The tail histidine residues, along with two previously identified lysine residues, account for a major part of the polyelectrolyte contribution to binding and for the nonspecific affinity of Mbp1 for DNA. Gln67 was shown to be a very important residue, which interacts in the minor groove of the target DNA. Systematic mutations of the DNA consensus binding sites showed that the CGCG core contributes most to recognition. Isothermal titration calorimetry revealed a strong temperature-dependent enthalpy change, with a Delta Cp of -1.3kJ mol(-1) K(-1), consistent with a specific binding mode and burial of surface area. Parsing the free energy contributions demonstrates that polyelectrolyte effects account for half of the total free energy at the physiological pH and salt concentration. We present a model for the origin of the sequence specificity and overall affinity of the protein that accounts for the observed thermodynamics.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1520-4995
pubmed:author
pubmed:issnType
Electronic
pubmed:day
17
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6378-85
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Thermodynamics and specificity of the Mbp1-DNA interaction.
pubmed:affiliation
J. G. Brown Cancer Center, University of Louisville, Louisville, Kentucky 40202, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't