Crystallization and preliminary diffraction analysis of Ca2+-calmodulin-drug and apocalmodulin-drug complexes |
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Authors: | Beata G. Vertessy,Zsolt Bö cskei,Veronika Harmath,Gá bor Ná ray-Szabó ,Judit Ová di |
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Abstract: | Ca2+-calmodulin is crystallized with two new and potent drugs: a bisindol derivative (KAR-2, 3”-(β-chloroethyl)-2”,4”-dioxo-3,5”-spiro-oxazolidino-4-deacetoxy-vinblastine) with antitumor activity and an arylalkylamine fendiline analogue (N-(3,3-diphenylpropyl)-N'-[1-(3,4-di-n-butoxy-phenyl)-ethyl]-1,3-diaminopropane) with anticalmodulin activity. The crystals diffract beyond 2.8 Å and differ in unit cell parameters from each other as well as from crystals of Ca2+-calmodulin or Ca2+-calmodulin-ligand complexes, as reported thus far. Attempts to crystallize Ca2+-free calmodulin without drugs failed, in consonance with earlier results; however, single Ca2+-free calmodulin crystals diffracting beyond 2.5 Å resolution were grown in the presence of KAR-2. Results indicate that binding of the two drugs to apocalmodulin or Ca2+-calmodulin may induce unique novel protein conformers, targets of further detailed X-ray studies. © 1997 Wiley-Liss Inc. |
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Keywords: | apocalmodulin calmodulin antagonists bisindol alkaloids fendiline analogues circular dichroism spectroscopy protein crystallization X-ray diffraction |
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