SECONDARY STRUCTURE OF THE DESIGNED PEPTIDE ALPHA-1 DETERMINED BY NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY

The solution structure of Alpha-1, a 12 amino acid designed peptide, has been investigated by one- and two-dimensional H-1 NMR spectroscopy. The peptide was designed as part of a project to investigate the formation of four-helix bundles. At high concentrations, the peptide forms an oligomer in which each peptide forms a regular helix, while at low concentrations the monomer is a random coil. These results are consistent with previous CD studies on the peptide. 1 The secondary structure in solution is the same for residues 1-9 as the recently determined crystal structure of Alpha-1(2) but differs for residues 10-12 which are extended in the crystal and helical in solution.