Related Experiment Video
Updated: Jul 2, 2026

Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
Solution structures of the N-terminal domain of yeast calmodulin: Ca2+-dependent conformational change and its
H Ishida1, K Takahashi, K Nakashima
1Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Abstract:
We have determined solution structures of the N-terminal half domain (N-domain) of yeast calmodulin (YCM0-N, residues 1-77) in the apo and Ca(2+)-saturated forms by NMR spectroscopy. The Ca(2+)-binding sites of YCM0-N consist of a pair of helix-loop-helix motifs (EF-hands), in which the loops are linked by a short beta-sheet. The binding of two Ca(2+) causes large rearrangement of the four alpha-helices and exposes the hydrophobic surface as observed for vertebrate calmodulin (CaM). Within the observed overall conformational similarity in the peptide backbone, several significant conformational differences were observed between the two proteins, which originated from the 38% disagreement in amino acid sequences. The beta-sheet in apo YCM0-N is strongly twisted compared with that in the N-domain of CaM, while it turns to the normal more stable conformation on Ca(2+) binding. YCM0-N shows higher cooperativity in Ca(2+) binding than the N-domain of CaM, and the observed conformational change of the beta-sheet is a possible cause of the highly cooperative Ca(2+) binding. The hydrophobic surface on Ca(2+)-saturated YCM0-N appears less flexible due to the replacements of Met51, Met71, and Val55 in the hydrophobic surface of CaM with Leu51, Leu71, and Ile55, which is thought to be one of reasons for the poor activation of target enzymes by yeast CaM.
More Related Videos
Related Concept Videos
Yeast Signaling
Protein Complexes with Interchangeable Parts
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
Overview of Secretory Vesicles
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Structure of Cadherins

