Solid-Phase Peptide Synthesis and 2D NMR Analysis of Unknown Tripeptides: An Advanced Undergraduate Synthesis and Spectroscopy Laboratory

Abstract

We describe a three-day advanced organic laboratory experience that includes the solid-phase synthesis of an unknown three amino acid polypeptide for junior/senior undergraduate chemistry majors. Students conduct a series of 1D and 2D NMR experiments (HSQC, HMBC, TOCSY) and analyze the data to identify the side chain residues of the peptide and the order in which they are coupled. Students gain important experience in solid-phase synthesis and in the use of advanced NMR techniques to identify the structure and order of amino acids in a polypeptide. Students demonstrate improved capacity to use 2D NMR spectra to identify unknown peptide structures and sequences. A green solid-phase synthesis procedure is also presented using nonsensitizing coupling reagents and green solvents. We also provide primary data for >45 tripeptides that can be used to support the solid-phase synthesis lab at universities that do not have advanced 2D NMR capabilities.