The interactions of calcium-calmodulin with two fragments of the N-terminal domains of the olfactory a-subunit and rod beta-subunit cyclic nucleotide-gated channels have been investigated using nuclear magnetic resonance spectroscopy. The results indicate that in the two cases both the N-terminal and the C-terminal calmodulin lobes are involved in the interaction. The olfactory cyclic nucleotide-gated channel segment forms a 1: 1 complex with calmodulin, whereas the rod fragment forms a 2:1 complex. The correlation times of the two complexes, as estimated by N-15 relaxation studies, are compatible with the observed stoichiometries. These results indicate differences in the mode of action by which calmodulin modulates the activity of both channels, and suggest either that the rod channel is modulated through a simultaneous interaction of two beta-subunits with calmodulin or that other regions of the N-terminus are necessarily implicated in the binding. (C) 2003 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.
Orsale, M., Melino, S.m., Contessa, G., Torre, V., Andreotti, G., Motta, A., et al. (2003). Two distinct calcium-calmodulin interactions with N-terminal regions of the olfactory and rod cyclic nucleotide-gated channels characterized by NMR spectroscopy. FEBS LETTERS, 548(1-3), 11-16 [10.1016/S0014-5793(03)00716-6].
Two distinct calcium-calmodulin interactions with N-terminal regions of the olfactory and rod cyclic nucleotide-gated channels characterized by NMR spectroscopy
MELINO, SONIA MICHAELA;PACI, MAURIZIO;DESIDERI, ALESSANDRO;CICERO, DANIEL OSCAR
2003-01-01
Abstract
The interactions of calcium-calmodulin with two fragments of the N-terminal domains of the olfactory a-subunit and rod beta-subunit cyclic nucleotide-gated channels have been investigated using nuclear magnetic resonance spectroscopy. The results indicate that in the two cases both the N-terminal and the C-terminal calmodulin lobes are involved in the interaction. The olfactory cyclic nucleotide-gated channel segment forms a 1: 1 complex with calmodulin, whereas the rod fragment forms a 2:1 complex. The correlation times of the two complexes, as estimated by N-15 relaxation studies, are compatible with the observed stoichiometries. These results indicate differences in the mode of action by which calmodulin modulates the activity of both channels, and suggest either that the rod channel is modulated through a simultaneous interaction of two beta-subunits with calmodulin or that other regions of the N-terminus are necessarily implicated in the binding. (C) 2003 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.