Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2001-2-22
pubmed:abstractText
Interactions that stabilize the native state of a protein have been studied by measuring the affinity between subdomain fragments with and without site-specific residue substitutions. A calbindin D(9k) variant with a single CNBr cleavage site at position 43 between its two EF-hand subdomains was used as a starting point for the study. Into this variant were introduced 11 site-specific substitutions involving hydrophobic core residues at the interface between the two EF-hands. The mutants were cleaved with CNBr to produce wild-type and mutated single-EF-hand fragments: EF1 (residues 1--43) and EF2 (residues 44--75). The interaction between the two EF-hands was studied using surface plasmon resonance (SPR) technology, which follows the rates of association and dissociation of the complex. Wild-type EF1 was immobilized on a dextran matrix, and the wild-type and mutated versions of EF2 were injected at several different concentrations. In another set of experiments, wild-type EF2 was immobilized and wild-type or mutant EF1 was injected. Dissociation rate constants ranged between 1.1 x 10(-5) and 1.0 x 10(-2) s(-1) and the association rate constants between 2 x 10(5) and 4.0 x 10(6) M(-1) s(-1). The affinity between EF1 and EF2 was as high as 3.6 x 10(11) M(-1) when none of them was mutated. For the 11 hydrophobic core mutants, a strong correlation (r = 0.999) was found between the affinity of EF1 for EF2 and the stability toward denaturation of the corresponding intact protein. The observed correlation implies that the factors governing the stability of the intact protein also contribute to the affinity of the bimolecular EF1-EF2 complex. In addition, the data presented here show that interactions among hydrophobic core residues are major contributors both to the affinity between the two EF-hand subdomains and to the stability of the intact domain.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
6
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1257-64
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11170451-Amino Acid Sequence, pubmed-meshheading:11170451-Amino Acid Substitution, pubmed-meshheading:11170451-Animals, pubmed-meshheading:11170451-Calcium-Binding Protein, Vitamin D-Dependent, pubmed-meshheading:11170451-Cattle, pubmed-meshheading:11170451-Cyanogen Bromide, pubmed-meshheading:11170451-EF Hand Motifs, pubmed-meshheading:11170451-Humans, pubmed-meshheading:11170451-Hydrolysis, pubmed-meshheading:11170451-Kinetics, pubmed-meshheading:11170451-Mice, pubmed-meshheading:11170451-Molecular Sequence Data, pubmed-meshheading:11170451-Mutagenesis, Site-Directed, pubmed-meshheading:11170451-Peptide Fragments, pubmed-meshheading:11170451-Protein Binding, pubmed-meshheading:11170451-Protein Structure, Tertiary, pubmed-meshheading:11170451-Rats, pubmed-meshheading:11170451-Sequence Homology, Amino Acid, pubmed-meshheading:11170451-Spectrometry, Fluorescence, pubmed-meshheading:11170451-Surface Plasmon Resonance, pubmed-meshheading:11170451-Thermodynamics
pubmed:year
2001
pubmed:articleTitle
Fragment complementation studies of protein stabilization by hydrophobic core residues.
pubmed:affiliation
Physical Chemistry 2, Chemical Centre, University of Lund, S-221 00 Lund, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't