Calcium-dependent conformational transition of calmodulin determined by Fourier transform infrared spectroscopy

The Ca2+-induced conformational changes in calmodulin (CaM) were monitored by Fourier transform infrared spectroscopy (FT-IR) at different molar ratios of Ca2+ to CaM. The results show that these changes occur in two distinctive transitions. The first transition involves significant changes in the o...

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Bibliographic Details
Published in:International journal of biological macromolecules 2013-05, Vol.56, p.57-61
Main Authors: Yu, Ting, Wu, Guangrong, Yang, Huayan, Wang, Jimin, Yu, Shaoning
Format: Article
Language:English
Subjects:
Calcium - pharmacology
Calmodulin
Calmodulin - chemistry
Conformational transition
Deuterium Exchange Measurement
FT-IR spectroscopy
H/D exchange
Protein Structure, Secondary
Spectroscopy, Fourier Transform Infrared - methods
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Summary:The Ca2+-induced conformational changes in calmodulin (CaM) were monitored by Fourier transform infrared spectroscopy (FT-IR) at different molar ratios of Ca2+ to CaM. The results show that these changes occur in two distinctive transitions. The first transition involves significant changes in the overall secondary structure with a small gain in solvent accessibility, and is completed after the second Ca2+ binds to both EF-hands of its C-terminal domain. The second transition is accompanied by CaM folding into a tighter, less hydrogen-exchangeable structure, and is completed by the addition of the fourth Ca2+ to have four Ca2+ per molecule. Particularly, α-helices in CaM–nCa2+(n=0, 1, 2) are less stable than those in CaM–nCa2+(n=3, 4).
ISSN:0141-8130
1879-0003
DOI:10.1016/j.ijbiomac.2013.02.004