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Direct Observation of Ca 2+ ‐Induced Calmodulin Conformational Transitions in Intact Xenopus laevis Oocytes by 19 F NMR Spectroscopy
Author(s) -
Ye Yansheng,
Liu Xiaoli,
Xu Guohua,
Liu Maili,
Li Conggang
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201500261
Subject(s) - calmodulin , xenopus , nuclear magnetic resonance spectroscopy , spectroscopy , population , chemistry , conformational change , myosin light chain kinase , crystallography , biophysics , myosin , stereochemistry , biology , biochemistry , physics , enzyme , demography , quantum mechanics , sociology , gene
The Ca 2+ ‐mediated conformational transition of the protein calmodulin (CaM) is essential to a variety of signal transduction pathways. Whether the transition in living cells is similar to that observed in buffer is not known. Here, we report the direct observation by 19 F NMR spectroscopy of the transition of the Ca 2+ ‐free and ‐bound forms in Xenopus laevis oocytes at different Ca 2+ levels. We find that the Ca 2+ ‐bound CaM population increased greatly upon binding the target protein myosin light‐chain kinase (MLCK) at the same Ca 2+ level. Paramagnetic NMR spectroscopy was also exploited for the first time to obtain long‐range structural constraints in cells. Our study shows that 19 F NMR spectroscopy can be used to obtain long‐range structural constraints in living eukaryotic cells and paves the way for quantification of protein binding constants.