Ca2+-myristoyl switch and membrane binding of chemically acylated neurocalcins.

Neurocalcin is a member of a novel family of neuronal calcium sensors that belongs to the superfamily of EF-hand Ca2+-binding proteins. Neurocalcin is myristoylated on its N-terminus in vivo and can associate with biological membranes in a calcium and myristoyl-dependent manner. This process known as “Ca2+-myristoyl switch” has been best described for the photoreceptor specific protein, recoverin, as well as for several other neuronal calcium sensors. Here, we used reversed micelles to chemically acylate nonmyristoylated neurocalcin at its N-terminus with fatty acids of different lengths (from C12 to C16). This approach allowed us to prepare neurocalcin derivatives in which a single fatty acid is selectively linked to the N-terminal glycine of the polypeptide chain through an amide bond. The membrane binding properties of the monoacylated neurocalcins were then examined by cosedimentation with phospholipid vesicles and direct binding to lipid monolayers by surface plasmon resonance spectroscopy (Biacore)....