Linked Life Data

11123919

Source:http://linkedlifedata.com/resource/pubmed/id/11123919

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
51
pubmed:dateCreated
2001-1-8
pubmed:abstractText
The Ca(2+) titration of the (15)N-labeled mutant V136G calmodulin has been monitored using (1)H-(15)N HSQC NMR spectra. Up to a [Ca(2+)]/[CaM] ratio of 2, the Ca(2+) ions bind predominantly to sites I and II on the N-domain in contrast with the behavior of the wild-type calmodulin where the C-terminal domain has the higher affinity for Ca(2+). Surprisingly, the Ca(2+)-binding affinity for the N-domain in the mutant calmodulin is greater than that for the N-domain in the wild-type protein. The mutated C-domain is observed as a mixture of unfolded, partially folded (site III occupied), and native-like folded (sites III and IV occupied) conformations, with relative populations dependent on the [Ca(2+)]/[CaM] ratio. The occupancy of site III independently of site IV in this mutant shows that the cooperativity of Ca(2+) binding in the C-domain is mediated by the integrity of the domain structure. Several NH signals from residues in the Ca(2+)-bound N-domain appear as two signals during the Ca(2+) titration indicating separate species in slow exchange, and it can be deduced that these result from the presence and absence of interdomain interactions in the mutant. It is proposed that an unfolded part of the mutated C-domain interacts with sites on the N-domain that normally bind to target proteins. This would also account for the increase in the Ca(2+) affinity for the N-domain in the mutant compared with the wild-type calmodulin. The results therefore show the wide-ranging effects of a point mutation in a single Ca(2+)-binding site, providing details of the involvement of individual residues in the calcium-induced folding reactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15920-31
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:11123919-Amino Acid Substitution, pubmed-meshheading:11123919-Animals, pubmed-meshheading:11123919-Binding Sites, pubmed-meshheading:11123919-Calcium, pubmed-meshheading:11123919-Calmodulin, pubmed-meshheading:11123919-Drosophila melanogaster, pubmed-meshheading:11123919-EF Hand Motifs, pubmed-meshheading:11123919-Glycine, pubmed-meshheading:11123919-Macromolecular Substances, pubmed-meshheading:11123919-Muscle, Smooth, pubmed-meshheading:11123919-Myosin-Light-Chain Kinase, pubmed-meshheading:11123919-Nitrogen Isotopes, pubmed-meshheading:11123919-Nuclear Magnetic Resonance, Biomolecular, pubmed-meshheading:11123919-Protein Conformation, pubmed-meshheading:11123919-Protein Folding, pubmed-meshheading:11123919-Protein Structure, Tertiary, pubmed-meshheading:11123919-Protons, pubmed-meshheading:11123919-Recombinant Proteins, pubmed-meshheading:11123919-Solutions, pubmed-meshheading:11123919-Thermodynamics, pubmed-meshheading:11123919-Valine
pubmed:year
2000
pubmed:articleTitle
Calcium-induced refolding of the calmodulin V136G mutant studied by NMR spectroscopy: evidence for interaction between the two globular domains.
pubmed:affiliation
Molecular Structure Division and Physical Biochemistry Division, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't