Mutation of Lys-75 affects calmodulin conformation

Marina V. Medvedeva, Oxsana V. Polyakova, D. Martin Watterson, Nikolai B. Gusev*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Some properties of synthetic calmodulin and its five mutants with replacement of Lys-75 were analyzed by means of electrophoresis, limited proteolysis and MALDI mass-spectrometry. A double mutant of calmodulin containing insert KGK between residues 80 and 81 and replacement of Lys-75 by Pro has a highly flexible central helix which is susceptible to trypsinolysis in the presence of Ca2+. Two mutants, K75P and K75E, having a distorted central helix demonstrate high resistance to trypsinolysis in the absence of Ca2+. Arg-90 and Arg-106 being the primary site of trypsinolysis of synthetic calmodulin are partially-protected in K75P and K75E mutants. The central helix of K75A and K75V mutants is stabilized by hydrophobic interactions between residues located in positions 71, 72 and 75. In the presence of Ca2+, the central helix of K75V is resistant to trypsinolysis. Mutations K75A and K75V decrease the rate of trypsinolysis of the central helix with a simultaneous increase of the rate of trypsinolysis in the C-terminal domain of calmodulin. It is concluded that the point mutation in the central helix has a long distance effect on the structure of calmodulin. Copyright (C) 1999 Federation of European Biochemical Societies.

Original languageEnglish (US)
Pages (from-to)139-143
Number of pages5
JournalFEBS Letters
Issue number1-2
StatePublished - Apr 30 1999


  • Calmodulin
  • Limited proteolysis
  • Mass-spectrometry
  • Mutant

ASJC Scopus subject areas

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


Dive into the research topics of 'Mutation of Lys-75 affects calmodulin conformation'. Together they form a unique fingerprint.

Cite this