2vay
From Proteopedia
Calmodulin complexed with CaV1.1 IQ peptide
Structural highlights
DiseaseCALM1_HUMAN The disease is caused by mutations affecting the gene represented in this entry. Mutations in CALM1 are the cause of CPVT4. The disease is caused by mutations affecting the gene represented in this entry. Mutations in CALM1 are the cause of LQT14. FunctionCALM1_HUMAN Calmodulin mediates the control of a large number of enzymes, ion channels, aquaporins and other proteins through calcium-binding. Among the enzymes to be stimulated by the calmodulin-calcium complex are a number of protein kinases and phosphatases. Together with CCP110 and centrin, is involved in a genetic pathway that regulates the centrosome cycle and progression through cytokinesis (PubMed:16760425). Mediates calcium-dependent inactivation of CACNA1C (PubMed:26969752). Positively regulates calcium-activated potassium channel activity of KCNN2 (PubMed:27165696).[1] [2] [3] [4] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCalmodulin binds to IQ motifs in the alpha(1) subunit of Ca(V)1.1 and Ca(V)1.2, but the affinities of calmodulin for the motif and for Ca(2+) are higher when bound to Ca(V)1.2 IQ. The Ca(V)1.1 IQ and Ca(V)1.2 IQ sequences differ by four amino acids. We determined the structure of calmodulin bound to Ca(V)1.1 IQ and compared it with that of calmodulin bound to Ca(V)1.2 IQ. Four methionines in Ca(2+)-calmodulin form a hydrophobic binding pocket for the peptide, but only one of the four nonconserved amino acids (His-1532 of Ca(V)1.1 and Tyr-1675 of Ca(V)1.2) contacts this calmodulin pocket. However, Tyr-1675 in Ca(V)1.2 contributes only modestly to the higher affinity of this peptide for calmodulin; the other three amino acids in Ca(V)1.2 contribute significantly to the difference in the Ca(2+) affinity of the bound calmodulin despite having no direct contact with calmodulin. Those residues appear to allow an interaction with calmodulin with one lobe Ca(2+)-bound and one lobe Ca(2+)-free. Our data also provide evidence for lobe-lobe interactions in calmodulin bound to Ca(V)1.2. Determinants in CaV1 channels that regulate the Ca2+ sensitivity of bound calmodulin.,Halling DB, Georgiou DK, Black DJ, Yang G, Fallon JL, Quiocho FA, Pedersen SE, Hamilton SL J Biol Chem. 2009 Jul 24;284(30):20041-51. Epub 2009 May 27. PMID:19473981[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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