Crystal and solution structure, stability and post-translational modifications of collapsin response mediator protein 2

Authors


  • Database
    The coordinates and structure factors have been deposited in the Protein Data Bank under the accession code 2VM8

P. Kursula, Department of Biochemistry, University of Oulu, P.O. Box 3000, FIN-90014 Oulu, Finland
Fax: +358 8 5531141
Tel: +358 44 5658288
E-mail: petri.kursula@oulu.fi

Abstract

The collapsin response mediator protein 2 (CRMP-2) is a central molecule regulating axonal growth cone guidance. It interacts with the cytoskeleton and mediates signals related to myelin-induced axonal growth inhibition. CRMP-2 has also been characterized as a constituent of neurofibrillary tangles in Alzheimer’s disease. CD spectroscopy and thermal stability assays using the Thermofluor method indicated that Ca2+ and Mg2+ affect the stability of CRMP-2 and prevent the formation of β-aggregates upon heating. Gel filtration showed that the presence of Ca2+ or Mg2+ promoted the formation of CRMP-2 homotetramers, and this was further proven by small-angle X-ray scattering experiments, where a 3D solution structure for CRMP-2 was obtained. Previously, we described a crystal structure of human CRMP-2 complexed with calcium. In the present study, we determined the structure of CRMP-2 in the absence of calcium at 1.9 Å resolution. When Ca2+ was omitted, crystals could only be grown in the presence of Mg2+ ions. By a proteomic approach, we further identified a number of post-translational modifications in CRMP-2 from rat brain hippocampus and mapped them onto the crystal structure.

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