Evidence for calmodulin inter-domain compaction in solution induced by W-7 binding

Masanori Osawa, Shigeo Kuwamoto, Yoshinobu Izumi, Kyoko L. Yap, Mitsuhiko Ikura, Tadao Shibanuma, Hisayuki Yokokura, Hiroyoshi Hidaka, Norio Matsushima

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Small-angle X-ray scattering and nuclear magnetic resonance were used to investigate the structural change of calcium-bound calmodulin (Ca2+/CaM) in solution upon binding to its antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7). The radius of gyration was 17.4±0.3 A for Ca2+/CaM-W-7 with a molar ratio of 1:5 and 20.3±0.7 A for Ca2+/CaM. Comparison of the radius of gyration and the pair distance distribution function of the Ca2+/CaM-W-7 complex with those of other complexes indicates that binding of two W-7 molecules induces a globular shape for Ca2+/CaM, probably caused by an inter-domain compaction. The results suggest a tendency for Ca2+/CaM to form a globular structure in solution, which is inducible by a small compound like W-7. Copyright (C) 1999 Federation of European Biochemical Societies.

Original languageEnglish
Pages (from-to)173-177
Number of pages5
JournalFEBS Letters
Issue number2-3
Publication statusPublished - 1999 Jan 15



  • Calmodulin-W-7 complex
  • Conformational change
  • Globular structure
  • Small-angle X-ray scattering

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

Cite this

Osawa, M., Kuwamoto, S., Izumi, Y., Yap, K. L., Ikura, M., Shibanuma, T., Yokokura, H., Hidaka, H., & Matsushima, N. (1999). Evidence for calmodulin inter-domain compaction in solution induced by W-7 binding. FEBS Letters, 442(2-3), 173-177. https://doi.org/10.1016/S0014-5793(98)01637-8