Linked Life Data

12653564

Source:http://linkedlifedata.com/resource/pubmed/id/12653564

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2003-3-25
pubmed:abstractText
We have examined the metal ion-binding domains from rat alpha and beta parvalbumin. We find that the CD-EF fragments differ markedly in their tendency to self-associate. Whereas Ca(2+)-free alpha CD-EF is monomeric, the Ca(2+)-free beta peptide dimerizes weakly (K(2) = 2400 +/- 200 M(-1)). In buffer containing 1.0 mM Ca(2+), the apparent dimerization constant for beta CD-EF (191,000 +/- 29,000 M(-1)) is more than 50 times that of alpha (3400 +/- 200 M(-1)). Alpha CD-EF binds two Ca(2+) with positive cooperativity. Titration calorimetry data afford binding constants of 3.7(0.1) x 10(3) M(-1) and 8.6(0.2) x 10(4) M(-1). Beta CD-EF also binds two Ca(2+) cooperatively but with lower affinity. Equilibrium dialysis yields Adair constants of 4.2(0.1) x 10(3) and 6.1(0.2) x 10(3) M(-1). Significantly, the difference in Ca(2+) affinity is substantially smaller than that observed for the full-length proteins-suggesting that the AB domain can modulate divalent ion affinity. Analysis of beta calorimetry data requires explicit consideration of the self-association behavior. Data collected at low CD-EF concentration are consistent with preferential occupation of the EF site, dimerization of singly bound monomers, and cooperative filling of the CD sites. At higher concentrations, apo-protein dimerization can apparently precede cooperative occupation of the EF sites. In the presence of Ca(2+), alpha CD-EF exhibits higher thermal stability, consistent with its higher Ca(2+) affinity. However, the beta melting temperature shows greater concentration dependence, consistent with its greater tendency to dimerize. Neither fragment exhibits a sigmoidal melting curve in the Ca(2+)-free state, suggesting that the apo-peptides are disordered.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3594-607
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Characterization of the metal ion-binding domains from rat alpha- and beta-parvalbumins.
pubmed:affiliation
Department of Biochemistry, University of Missouri-Columbia, Columbia, Missouri 65211, USA. henzlm@missouri.edu
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't