Carboproteins: A 4-α-helix bundle protein model assembled on a -galactopyranoside template

We have recently introduced the concept of monosaccharides as templates for de novo design of protein models and described the synthesis of a model ‘carbopeptide’. Here, we report the synthesis of a 64 amino acid (AA) ‘carboprotein’ by chemoselective ligation of a C-terminal hexadecapeptide aldehyde to a tetra-aminooxy functionalized methyl α- -galactopyranoside ( -Galp) template. Biophysical characterizations by CD spectroscopy and NMR amide H–D exchange experiments indicated that the four-stranded carboprotein forms a 4-α-helix bundle structure.