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Conformational requirements for Ca 2+ /calmodulin binding and activation of myosin light chain kinase
Author(s) -
Padre Roanna C,
Stull James T
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01434-4
Subject(s) - calmodulin , myosin light chain kinase , biochemistry , chemistry , myosin , kinase , protein kinase a , helix (gastropod) , binding site , phosphorylation , biophysics , immunoglobulin light chain , biology , enzyme , genetics , ecology , snail , antibody
Myosin light chain kinase contains a regulatory segment consisting of an autoinhibitory region and a calmodulin‐binding sequence that folds back on its catalytic core to inhibit kinase activity. It has been proposed that α‐helix formation may be involved in displacement of the regulatory segment and activation of the kinase by Ca 2+ /calmodulin. Proline mutations were introduced at putative non‐interacting residues in the regulatory segment to disrupt helix formation. Substitution of proline residues immediately N‐terminal of the Trp in the calmodulin‐binding sequence had most significant effects on Ca 2+ /calmodulin binding and activation. Formation of an α‐helix in this region upon Ca 2+ /calmodulin binding may be necessary for displacement of the regulatory segment allowing phosphorylation of myosin regulatory light chain.