Calcium-induced structural changes and domain autonomy in calmodulin.
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.
Finn
B E
BE
Department of Physical Chemistry, Lund University, Sweden.
Evenäs
J
J
Drakenberg
T
T
Waltho
J P
JP
Thulin
E
E
Forsén
S
S
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
D002147:Calmodulin; D012996:Solutions; D002118:Calcium