Linked Life Data

1637811

Source:http://linkedlifedata.com/resource/pubmed/id/1637811

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
29
pubmed:dateCreated
1992-8-28
pubmed:abstractText
The calcium-binding properties of equine and pigeon lysozyme as well as those of bovine and human alpha-lactalbumin were investigated by 43Ca NMR spectroscopy. All proteins were found to contain one high-affinity calcium-binding site. The chemical shifts, line widths, relaxation times (T1 and T2), and quadrupole coupling constants for the respective 43Ca NMR signals were quite similar; this is indicative of a high degree of homology between the strong calcium-binding sites of these four proteins. The measured chemical shifts (delta approximately -3 to -7 ppm) and quadrupole coupling constants (chi approximately 0.7-0.8 MHz) are quite distinct from those observed for typical EF-hand calcium-binding proteins, suggesting a different geometry for the calcium-binding loops. The correlation times for bound calcium ions in these proteins were on the order of 4-8 ns, indicating that the flexibilities of these binding sites are limited. The apparent pKa values for the high-affinity sites ranged from 3.4 to 4.7, confirming the participation of carboxylate-containing residues in the coordination of the calcium ion. Competition experiments with EDTA showed that the affinities of these proteins for calcium follow the series bovine alpha-lactalbumin approximately human alpha-lactalbumin greater than pigeon lysozyme greater than equine lysozyme (KD approximately 5 x 10(-8) to 10(-6) M). Evidence for the existence of a second weak calcium-binding site (KD = 3 x 10(-3) M) was obtained for bovine alpha-lactalbumin, but not for the other proteins studied.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6761-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Calcium-43 NMR studies of calcium-binding lysozymes and alpha-lactalbumins.
pubmed:affiliation
Department of Biological Sciences, University of Calgary, Alberta, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't