Expression, purification, crystallization and preliminary X-ray crystallographic analysis of the extracellular olfactomedin domain of gliomedin

Crystallographic anomalous diffraction data for the experimental phasing of two myelin proteins, gliomedin and periaxin

We present datasets that can be used for the experimental phasing of crystal structures of two myelin proteins. The structures were recently described in the articles “Periaxin and AHNAK nucleoprotein 2 form intertwined homodimers through domain swapping” (H. Han, P. Kursula, 2014) [1] and “The olfactomedin domain from gliomedin is a β-propeller with unique structural properties” (H. Han, P. Kursula, 2015) [2]. Crystals of periaxin were derivatized with tungsten and xenon prior to data collection, and diffraction data for these crystals are reported at 3 and 1 wavelengths, respectively. Crystallographic data for two different pressurizing times for xenon are provided. Gliomedin was derivatized with platinum, and data for single-wavelength anomalous dispersion are included. The data can be used to repeat the phasing experiments, to analyze heavy atom binding sites in proteins, as well as to optimize future derivatization experiments of protein crystals with these and other heavy-atom compounds.

The olfactomedin domain from gliomedin is a β-propeller with unique structural properties

All members of the olfactomedin (OLF) family have a conserved extracellular OLF domain, for which a structure has not been available. We present here the crystal structure of the OLF domain from gliomedin. Gliomedin is a protein expressed by Schwann cells in peripheral nerves, important for the formation of the nodes of Ranvier. Gliomedin interacts with neuronal cell adhesion molecules, such as neurofascin, but the structural details of the interaction are not known. The structure of the OLF domain presents a five-bladed β-propeller fold with unusual geometric properties. The symmetry of the structure is not 5-fold, but rather reveals a twisted arrangement. The conserved top face of the gliomedin OLF domain is likely to be important for binding to neuronal ligands. Our results provide a structural basis for the functions of gliomedin in Schwann cells, enable the understanding of the role of the gliomedin OLF domain in autoimmune neuropathies, and unravel the locations of human disease-causing mutations in other OLF family members, including myocilin.