Linked Life Data

11697728

Source:http://linkedlifedata.com/resource/pubmed/id/11697728

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2001-11-7
pubmed:abstractText
The solution structure, thermodynamic stability and hydrodynamic properties of the 55-residue C-terminal domain of UvrB that interacts with UvrC during excision repair in E. coli have been determined using a combination of high resolution NMR, ultracentrifugation, 15N NMR relaxation, gel permeation, NMR diffusion, circular dichroism and differential scanning calorimetry. The subunit molecular weight is 7,438 kDa., compared with 14.5+/-1.0 kDa. determined by equilibrium sedimentation, indicating a dimeric structure. The structure determined from NMR showed a stable dimer of anti-parallel helical hairpins that associate in an unusual manner, with a small and hydrophobic interface. The Stokes radius of the protein decreases from a high plateau value (ca. 22 A) at protein concentrations greater than 4 microM to about 18 A at concentrations less than 0.1 microM. The concentration and temperature-dependence of the far UV circular dichroism show that the protein is thermally stable (Tm ca. 71.5 degrees C at 36 microM). The simplest model consistent with these data was a dimer dissociating into folded monomers that then unfolds co-operatively. The van't Hoff enthalpy and dissociation constant for both transition was derived by fitting, with deltaH1=23 kJ mol(-1). K1(298)=0.4 microM and deltaH2= 184 kJ mol(-1). This is in good agreement with direct calorimetric analysis of the thermal unfolding of the protein, which gave a calorimetric enthalpy change of 181 kJ mol(-1) and a van't Hoff enthalpy change of 354 kJ mol(-1), confirming the dimer to monomer unfolding. The thermodynamic data can be reconciled with the observed mode of dimerisation. 15N NMR relaxation measurements at 14.1 T and 11.75 T confirmed that the protein behaves as an asymmetric dimer at mM concentrations, with a flexible N-terminal linker for attachment to the remainder of the UvrB protein. The role of dimerisation of this domain in the excision repair mechanism is discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0739-1102
pubmed:author
pubmed:issnType
Print
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
219-36
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:11697728-Amino Acid Sequence, pubmed-meshheading:11697728-Calorimetry, Differential Scanning, pubmed-meshheading:11697728-Circular Dichroism, pubmed-meshheading:11697728-DNA Helicases, pubmed-meshheading:11697728-DNA Repair, pubmed-meshheading:11697728-Dimerization, pubmed-meshheading:11697728-Endodeoxyribonucleases, pubmed-meshheading:11697728-Escherichia coli, pubmed-meshheading:11697728-Escherichia coli Proteins, pubmed-meshheading:11697728-Models, Molecular, pubmed-meshheading:11697728-Molecular Sequence Data, pubmed-meshheading:11697728-Nuclear Magnetic Resonance, Biomolecular, pubmed-meshheading:11697728-Protein Conformation, pubmed-meshheading:11697728-Protein Denaturation, pubmed-meshheading:11697728-Protein Structure, Quaternary, pubmed-meshheading:11697728-Protein Structure, Tertiary, pubmed-meshheading:11697728-Sequence Homology, Amino Acid, pubmed-meshheading:11697728-Solutions, pubmed-meshheading:11697728-Static Electricity, pubmed-meshheading:11697728-Thermodynamics
pubmed:year
2001
pubmed:articleTitle
Solution structure, hydrodynamics and thermodynamics of the UvrB C-terminal domain.
pubmed:affiliation
Randall Centre for Molecular Mechanisms of Cell Function, New Hunt's House, King's College, London, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't