Nogo goes in the pure water: solution structure of Nogo-60 and design of the structured and buffer-soluble Nogo-54 for enhancing CNS regeneration.
The inability to determine the structure of the buffer-insoluble Nogo extracellular domain retarded further design of Nogo receptor (NgR) antagonists to treat CNS axonal injuries. Very surprisingly, we recently discovered that Nogo-60 was soluble and structured in salt-free water, thus allowing the determination of the first Nogo structure by heteronuclear NMR spectroscopy. Nogo-60 adopts an unusual helical structure with the N- and C-terminal helices connected by a long middle helix. While the N-helix has no contact with the rest of the molecule, the C-helix flips back to pack against the 20-residue middle helix. This packing appears to trigger the formation of the stable Nogo-60 structure because Nogo-40 with the last helix truncated is unstructured. The Nogo-60 structure offered us rationales for further design of the structured and buffer-soluble Nogo-54, which may be used as a novel NgR antagonist. Furthermore, our discovery may imply a general solution to solubilizing a category of buffer-insoluble proteins for urgent structural investigations.
Li
Minfen
M
Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore.
Liu
Jingxian
J
Song
Jianxing
J
D000818:Animals; D002490:Central Nervous System / Q000293:injuries / Q000502:physiology; D002942:Circular Dichroism; D058851:GPI-Linked Proteins; D006801:Humans; D009185:Myelin Proteins / Q000737:chemistry* / Q000502:physiology; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology; D000070798:Nogo Proteins; D000070816:Nogo Receptor 1; D019906:Nuclear Magnetic Resonance, Biomolecular; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000502:physiology; D012995:Solubility; D014867:Water
D058851:GPI-Linked Proteins; D009185:Myelin Proteins; D000070798:Nogo Proteins; D000070816:Nogo Receptor 1; C000603199:RTN4 protein, human; C486580:RTN4R protein, human; D011956:Receptors, Cell Surface; D014867:Water