Structural Properties of the Myelin-Associated Glycoprotein Ectodomain |
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| Authors: | John Attia&dagger ,Les Hicks&Dagger ,Kimio Oikawa&Dagger ,Cyril M. Kay&Dagger ,Robert J. Dunn |
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| Affiliation: | Center for Research in Neuroscience, McGill University, Montreal General Hospital Research Institute, Montreal, Quebec;Department of Medical Genetics, University of Toronto, Toronto, Ontario;Medical Research Council of Canada Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada |
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| Abstract: | Abstract: Myelin-associated glycoprotein (MAG) has been proposed to mediate adhesive interactions during myelin development. We have used the baculovirus expression system to produce a truncated form of this molecule [soluble extracellular domain of MAG (sMAG)] consisting of the complete extracellular ectodomain. Spectroscopic studies indicate a high β-sheet content, consistent with the prediction of Ig-like structure. Hydrodynamic studies indicate an asymmetric monomer, with a Stokes radius of 4.1–4.6 nm, a sedimentation coefficient of 3.6S, and a frictional ratio of ∼1.6. We postulate that the outer two Ig-like domains form a unit that folds back over the rest of the molecule. Fluorescence quenching studies indicate that sMAG interacts with divalent cations and may have a functional lectin domain. |
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| Keywords: | Myelin Baculovirus Sedimentation analysis Fluorescence quenching Ig fold |
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