title: Calcium-induced structural changes and domain autonomy in calmodulin.
abstract: We have determined the solution structures of the apo and (Ca2+)2 forms of the carboxy-terminal domain of calmodulin using multidimensional heteronuclear nuclear magnetic resonance spectroscopy. The results show that both forms adopt well-defined structures with essentially equal secondary structure. A comparison of the structures of the two forms shows that Ca2+ binding causes major rearrangements of the secondary structure elements with changes in inter-residue distances of up to 15 A and exposure of the hydrophobic interior of the four-helix bundle. Comparisons with previously determined high-resolution X-ray structures and models of calmodulin indicate that this domain is structurally autonomous.
authors.affiliation: Department of Physical Chemistry, Lund University, Sweden.
authors.forename: B E
authors.initials: BE
authors.lastname: Finn
authors.forename: J
authors.initials: J
authors.lastname: Evenäs
authors.forename: T
authors.initials: T
authors.lastname: Drakenberg
authors.forename: J P
authors.initials: JP
authors.lastname: Waltho
authors.forename: E
authors.initials: E
authors.lastname: Thulin
authors.forename: S
authors.initials: S
authors.lastname: Forsén
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism*; D002417:Cattle; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011487:Protein Conformation; D012996:Solutions; D013329:Structure-Activity Relationship
chemical_list: D002147:Calmodulin; D012996:Solutions; D002118:Calcium