Matthew Ranaghan - A Highly Conserved Cysteine of Neuronal Calcium-sensing Proteins Controls Cooperative Binding of Calcium to Recoverin.

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      Publication Details (including relevant citation   information):

      Ranaghan, M.   J.,  Kumar,   R. P., Chakrabarti, K. S., Buosi, V., Kern, D., and Oprian, D. D.   (2013) J. Biol.   Chem. 288 (50): 36160-7.

      Abstract:

        Recoverin, a 23-kDa Ca2+-binding protein of the   neuronal calcium sensing (NCS) family, inhibits rhodopsin kinase,   a Ser/ Thr kinase responsible for termination of photoactivated   rho- dopsin in rod photoreceptor cells. Recoverin has two   functional EF hands and a myristoylated N terminus. The myristoyl   chain imparts cooperativity to the Ca2+-binding sites   through an allosteric mechanism involving a conformational   equilibrium between R and T states of the protein.   Ca2+ binds preferentially to the R state; the   myristoyl chain binds preferentially to the T state. In the   absence of myristoylation, the R state predomi- nates, and   consequently, binding of Ca2+ to the non-myristoylated   protein is not cooperative. We show here that a mutation, C39A,   of a highly conserved Cys residue among NCS proteins, increases   the apparent cooperativity for binding of Ca2+ to non-   myristoylated recoverin. The binding data can be explained by an   effect on the T/R equilibrium to favor the T state without   affecting the intrinsic binding constants for the two   Ca2+ sites.

      Address (URL): http://dx.doi.org/10.1074/jbc.M113.524355