{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T06:29:09Z","timestamp":1779344949144,"version":"3.51.4"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"2","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1996,6,1]]},"abstract":"<jats:p>The binding of Ca2+\u2013 and Ba2+\u2013calmodulin to caldesmon and its functional consequence was investigated with three different calmodulin mutants. Two calmodulin mutants have pairs of cysteine residues substituted and oxidized to a disulphide bond in either the N- or C-terminal lobe (C41\/75 and C85\/112). The third mutant has phenylalanine-92 replaced by alanine (F92A). Binding measurements in the presence of Ca2+ by separation on native gels and by carbodiimide-induced cross-linking showed a lower affinity for caldesmon in all the mutants. When Ca2+ was replaced by Ba2+ the affinity of calmodulin for caldesmon was further reduced. The ability of Ca2+\u2013calmodulin to release caldesmon's inhibition of the actin\u2013tropomyosin-activated myosin ATPase was virtually abolished by mutation of phenylalanine-92 to alanine or by replacing Ba2+ for Ca2+ in native calmodulin. Both cysteine mutants retained their functional ability, but the increased concentration needed for 50% release of caldesmon inhibition reflected their decreased affinity. Ca2+\u2013calmodulin produced a broadening in the signals of the NMR spectrum of the 10 kDa Ca2+\u2013calmodulin-binding C-terminal fragment of caldesmon arising from tryptophans -749 and -779 and caused an enhancement of maximum tryptophan fluorescence of 49% and a 16 nm blue shift of the maximum. Ca2+\u2013calmodulin F92A produced a change in wavelength of 4 nm but no change in maximum, whereas Ca2+\u2013calmodulin C41\/75 binding produced a decrease in fluorescence with no shift of the maximum. We conclude that functional binding of Ca2+\u2013calmodulin to caldesmon requires multiple interaction sites on both molecules. However, some structural modification in calmodulin does not abolish the caldesmon-related functionality. This suggests that various EF hand proteins can substitute for the calmodulin molecule.<\/jats:p>","DOI":"10.1042\/bj3160413","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T21:49:22Z","timestamp":1439243362000},"page":"413-420","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Multiple-sited interaction of caldesmon with Ca2+-calmodulin"],"prefix":"10.1042","volume":"316","author":[{"given":"Pia A. J.","family":"HUBER","sequence":"first","affiliation":[{"name":"Imperial College, National Heart and Lung Institute, Dovehouse Street, London SW3 6LY, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mohammed","family":"EL-MEZGUELDI","sequence":"additional","affiliation":[{"name":"Imperial College, National Heart and Lung Institute, Dovehouse Street, London SW3 6LY, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zenon","family":"GRABAREK","sequence":"additional","affiliation":[{"name":"Muscle Research Group, Boston Biomedical Research Institute, Boston, MA 02114, U.S.A."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David A.","family":"SLATTER","sequence":"additional","affiliation":[{"name":"Department of Physiology, Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Barry A.","family":"LEVINE","sequence":"additional","affiliation":[{"name":"Department of Physiology, Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Steven B.","family":"MARSTON","sequence":"additional","affiliation":[{"name":"Imperial College, National Heart and Lung Institute, Dovehouse Street, London SW3 6LY, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/316\/2\/413\/619710\/bj3160413.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/316\/2\/413\/619710\/bj3160413.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,23]],"date-time":"2021-11-23T23:30:40Z","timestamp":1637710240000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/316\/2\/413\/31814\/Multiple-sited-interaction-of-caldesmon-with-Ca2"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1996,6,1]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1996,6,1]]}},"URL":"https:\/\/doi.org\/10.1042\/bj3160413","relation":{},"ISSN":["0264-6021","1470-8728"],"issn-type":[{"value":"0264-6021","type":"print"},{"value":"1470-8728","type":"electronic"}],"subject":[],"published":{"date-parts":[[1996,6,1]]}}}