@article {1815,
	title = {Peptide binding by a fragment of calmodulin composed of EF-hands 2 and 3},
	journal = {Biochemistry},
	volume = {46},
	number = {29},
	year = {2007},
	note = {Lakowski, Ted M. Lee, Gregory M. Lelj-Garolla, Barbara Okon, Mark Reid, Ronald E. McIntosh, Lawrence P.},
	month = {Jul},
	pages = {8525-8536},
	abstract = {Calmodulin (CaM) is composed of two EF-hand domains tethered by a flexible linker. Upon Ca2+-binding, a fragment of CaM encompassing EF-hands 2 and 3 (CaM2/3; residues 46-113) folds into a structure remarkably similar to the N- and C-domains of CaM. In this study, we demonstrate that Ca2+-ligated CaM2/3 can also bind to a peptide representing the CaM-recognition sequence of skeletal muscle myosin light chain kinase (M13) with an equimolar stoichiometry and a dissociation constant of 0.40 ( 0.05 AM. On the basis of an analytical ultracentrifugation measurement, the resulting complex exists as an equilibrium mixture of 2: 2 heterotetrameric and 1:1 heterodimeric species. Chemical shift perturbation mapping indicates that, similar to CaM, the peptide associates with a hydrophobic groove crossing both EF-hands in CaM2/3. However, upon binding the M13 peptide, many residues in CaM2/3 yielded two equal intensity NMR signals with the same N-15 relaxation properties. Thus, the 2: 2 CaM2/3-M13 tetramer, which predominates under the conditions used for these studies, is asymmetric with each component adopting spectroscopically distinguishable conformations within the complex. CaM2/3 also weakly stimulates the phosphatase activity of calcineurin and inhibits stimulation by native CaM. These studies highlight the remarkable plasticity of EF-hand association and expand the diverse repertoire of mechanisms possible for CaM-target protein interactions.},
	isbn = {0006-2960},
	url = {<Go to ISI>://000248073200004},
	author = {Lakowski, T. M. and Lee, G. M. and Lelj-Garolla, B. and Okon, M. and Reid, R. E. and McIntosh, L. P.}
}
