Linked Life Data

8539253

Source:http://linkedlifedata.com/resource/pubmed/id/8539253

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1996-2-8
pubmed:abstractText
The structural and energetic perturbations caused by cavity-creating mutations (Leu-41-->Val and Leu-41-->Ala) in the dimeric 4-alpha-helical-bundle protein ROP have been characterized by CD spectroscopy and differential scanning calorimetry (DSC). Deconvolution of the CD spectra showed a decrease in alpha-helicity as a result of the amino acid exchanges that follows qualitatively the overall decrease in conformational stability. Transition enthalpies are sensitive probes of the energetic change associated with point mutations. delta H zero values at the respective transition temperatures, T 1/2 (71.0, 65.3, and 52.9 degrees C at 0.5 mg/ml) decrease from 580 +/- 20 to 461 +/- 20 kJ/(mol of dimer) and 335 +/- 20 kJ/(mol of dimer) for wild-type ROP (Steif, C., Weber, P., Hinz, H.-J., Flossdorf, J., Cesareni, G., Kokkinidis, M. Biochemistry 32:3867-3876, 1993), L41V, and L41A, respectively. The conformational stabilities at 25 degrees C expressed by the standard Gibbs energies of denaturation, delta GzeroD, are 71.7, 61.1, and 46.1 kJ/(mol of dimer). The corresponding transition enthalpies have been obtained from extrapolation using the cDp(T) and cNp(T) functions. Their values at 25 degrees C are 176.3, 101.9, and 141.7 kJ/(mol of dimer) for wild-type ROP, L41V, and L41A, respectively. When the stability perturbation resulting from the cavity creating mutations is referred to the exchange of 1 mol of CH2 group, the average delta delta GzeroD value is -5.0 +/- 1 kJ/(mol of CH2 group). This decrease in conformation stability suggests that dimeric ROP exhibits the same susceptibility to Leu-->Val and Leu-->Ala exchanges as small monomeric proteins. Careful determinations of the partial specific heat capacities of wild-type and mutated protein solutions suggest that the mutational effects are predominantly manifested in the native rather than the unfolded state.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0887-3585
pubmed:author
pubmed:issnType
Print
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
83-96
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:8539253-Alanine, pubmed-meshheading:8539253-Bacterial Proteins, pubmed-meshheading:8539253-Calorimetry, Differential Scanning, pubmed-meshheading:8539253-Circular Dichroism, pubmed-meshheading:8539253-Energy Transfer, pubmed-meshheading:8539253-Enzyme Stability, pubmed-meshheading:8539253-Hot Temperature, pubmed-meshheading:8539253-Leucine, pubmed-meshheading:8539253-Models, Molecular, pubmed-meshheading:8539253-Mutation, pubmed-meshheading:8539253-Protein Conformation, pubmed-meshheading:8539253-Protein Folding, pubmed-meshheading:8539253-RNA-Binding Proteins, pubmed-meshheading:8539253-Recombinant Proteins, pubmed-meshheading:8539253-Software, pubmed-meshheading:8539253-Structure-Activity Relationship, pubmed-meshheading:8539253-Temperature, pubmed-meshheading:8539253-Thermodynamics, pubmed-meshheading:8539253-Valine
pubmed:year
1995
pubmed:articleTitle
Effects of cavity-creating mutations on conformational stability and structure of the dimeric 4-alpha-helical protein ROP: thermal unfolding studies.
pubmed:affiliation
Institut für Physikalische Chemie, Westfälischen Wilhelms-Universität, Münster, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't