Structural studies of human Naked2: a biologically active intrinsically unstructured protein.
Naked1 and 2 are two mammalian orthologs of Naked Cuticle, a canonical Wnt signaling antagonist in Drosophila. Naked2, but not Naked1, interacts with transforming growth factor-alpha (TGFalpha) and escorts TGFalpha-containing vesicles to the basolateral membrane of polarized epithelial cells. Full-length Naked2 is poorly soluble. Since most functional domains, including the Dishevelled binding region, EF-hand, vesicle recognition, and membrane targeting motifs, reside in the N-terminal half of the protein, we expressed and purified the first 217 residues of human Naked2 and performed a functional analysis of this fragment. Its circular dichroism (CD) and nuclear magnetic resonance (NMR) spectra showed no evidence of secondary and/or tertiary structure. The fragment did not bind calcium or zinc. These results indicate that the N-terminal half of Naked2 behaves as an intrinsically unstructured protein.
Hu
Tianhui
T
Department of Medicine and Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Krezel
Andrzej M
AM
Li
Cunxi
C
Coffey
Robert J
RJ
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D006801:Humans; D008968:Molecular Conformation; D011487:Protein Conformation; D012995:Solubility; D051153:Wnt Proteins / Q000737:chemistry*
D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; C449092:NKD2 protein, human; D051153:Wnt Proteins