5t7c
Solution structure of calcium free, myristoylated visinin-like protein 3
Structural highlights
FunctionHPCL1_HUMAN May be involved in the calcium-dependent regulation of rhodopsin phosphorylation. Publication Abstract from PubMedVisinin-like protein 3 (VILIP-3) belongs to a family of Ca2+-myristoyl switch proteins that regulate signal transduction in the brain and retina. Here we analyze Ca2+ binding, characterize Ca2+-induced conformational changes, and determine the NMR structure of myristoylated VILIP-3. Three Ca2+ bind cooperatively to VILIP-3 at EF2, EF3 and EF4 (KD = 0.52 muM and Hill slope of 1.8). NMR assignments, mutagenesis and structural analysis indicate that the covalently attached myristoyl group is solvent exposed in Ca2+-bound VILIP-3, whereas Ca2+-free VILIP-3 contains a sequestered myristoyl group that interacts with protein residues (E26, Y64, V68), which are distinct from myristate contacts seen in other Ca2+-myristoyl switch proteins. The myristoyl group in VILIP-3 forms an unusual L-shaped structure that places the C14 methyl group inside a shallow protein groove, in contrast to the much deeper myristoyl binding pockets observed for recoverin, NCS-1 and GCAP1. Thus, the myristoylated VILIP-3 protein structure determined in this study is quite different from those of other known myristoyl switch proteins (recoverin, NCS-1, and GCAP1). We propose that myristoylation serves to fine tune the three-dimensional structures of neuronal calcium sensor proteins as a means of generating functional diversity. Structure and Calcium Binding Properties of a Neuronal Calcium-Myristoyl Switch Protein, Visinin-Like Protein 3.,Li C, Lim S, Braunewell KH, Ames JB PLoS One. 2016 Nov 7;11(11):e0165921. doi: 10.1371/journal.pone.0165921., eCollection 2016. PMID:27820860[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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