| http://purl.uniprot.org/citations/8631777 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | http://purl.uniprot.org/core/Journal_Citation |
| http://purl.uniprot.org/citations/8631777 | http://www.w3.org/2000/01/rdf-schema#comment | "Calcium-dependent regulation of intracellular processes is mediated by proteins that on binding Ca2+ assume a new conformation, which enables them to bind to their specific target proteins and to modulate their function. Calmodulin (CaM) and troponin C, the two best characterized Ca2+-regulatory proteins, are members of the family of Ca2+-binding proteins utilizing the helix-loop-helix structural motif (EF-hand). Herzberg, Moult, and James (Herzberg, O., Moult, J., and James, M.N.G. (1986) J. Biol. Chem. 261, 2638-2644) proposed that the Ca2+-induced conformational transition in troponin C involves opening of the interface between the alpha-helical segments in the N-terminal domain of this protein. Here we have tested the hypothesis that a similar transition is the key Ca2+-induced regulatory event in calmodulin. Using site-directed mutagenesis we have substituted cysteine residues for Gln41 and Lys75 (CaM41/75) or Ile85 and Leu112 (CaM85/112) in the N-terminal and C-terminal domains, respectively, of human liver calmodulin. Based on molecular modeling, cysteines at these positions were expected to form intramolecular disulfide bonds in the Ca2+-free conformation of the protein, thus blocking the putative Ca2+-induced transition. We found that intramolecular disulfide bonds are readily formed in both mutants causing a decrease in affinity for Ca2+ and the loss of ability to activate target enzymes, phosphodiesterase and calcineurin. The regulatory activity is fully recovered in CaM41/75 and partially recovered in CaM85/112 upon reduction of the disulfide bonds with dithiothreitol and blocking the Cys residues by carboxyamidomethylation or cyanylation. These results indicate that the Ca2+-induced opening of the interfaces between helical segments in both domains of CaM is critical for its regulatory properties consistent with the Herzberg-Moult-James model."xsd:string |
| http://purl.uniprot.org/citations/8631777 | http://purl.org/dc/terms/identifier | "doi:10.1074/jbc.271.13.7479"xsd:string |
| http://purl.uniprot.org/citations/8631777 | http://purl.uniprot.org/core/author | "Grabarek Z."xsd:string |
| http://purl.uniprot.org/citations/8631777 | http://purl.uniprot.org/core/author | "Mabuchi Y."xsd:string |
| http://purl.uniprot.org/citations/8631777 | http://purl.uniprot.org/core/author | "Tan R.Y."xsd:string |
| http://purl.uniprot.org/citations/8631777 | http://purl.uniprot.org/core/date | "1996"xsd:gYear |
| http://purl.uniprot.org/citations/8631777 | http://purl.uniprot.org/core/name | "J Biol Chem"xsd:string |
| http://purl.uniprot.org/citations/8631777 | http://purl.uniprot.org/core/pages | "7479-7483"xsd:string |
| http://purl.uniprot.org/citations/8631777 | http://purl.uniprot.org/core/title | "Blocking the Ca2+-induced conformational transitions in calmodulin with disulfide bonds."xsd:string |
| http://purl.uniprot.org/citations/8631777 | http://purl.uniprot.org/core/volume | "271"xsd:string |
| http://purl.uniprot.org/citations/8631777 | http://www.w3.org/2004/02/skos/core#exactMatch | http://purl.uniprot.org/pubmed/8631777 |
| http://purl.uniprot.org/citations/8631777 | http://xmlns.com/foaf/0.1/primaryTopicOf | https://pubmed.ncbi.nlm.nih.gov/8631777 |
| http://purl.uniprot.org/uniprot/P0DP23#attribution-7D57DF3B761BA88CD00C8CE5C9AB7E0D | http://purl.uniprot.org/core/source | http://purl.uniprot.org/citations/8631777 |
| http://purl.uniprot.org/uniprot/P0DP24#attribution-7D57DF3B761BA88CD00C8CE5C9AB7E0D | http://purl.uniprot.org/core/source | http://purl.uniprot.org/citations/8631777 |
| http://purl.uniprot.org/uniprot/P0DP25#attribution-7D57DF3B761BA88CD00C8CE5C9AB7E0D | http://purl.uniprot.org/core/source | http://purl.uniprot.org/citations/8631777 |