The NH2 terminus of retinal recoverin is acylated by a small family of fatty acids

Recoverin is a recently identified Ca(2+)-binding protein that imparts Ca2+ sensitivity to vertebrate photoreceptor guanylate cyclase. In response to photo-induced depletion of intracellular cGMP and Ca2+, recoverin stimulates resynthesis of cGMP. Bovine retinal recoverin has now been analyzed by electrospray mass spectrometry (ESI-MS) for post-translational modifications that might influence its activity. Heterogeneous acylation was detected at the NH2 terminus of bovine retinal recoverin. The NH2-terminal glycine of each retinal recoverin molecule is linked to one of four different types of acyl groups. The most abundant is myristoleate (14:1), but 14:0, 14:2, and 12:0 acyl residues are also present.