Protein structure determination is imperative in discovering the etiology of diseases and disease progression. Many of these proteins are analyzed by x-ray crystallography, nuclear magnetic resonance (NMR), and mass spectrometry. In x-ray crystallography, small atoms like carbon, hydrogen, and oxygen may provide poor resolution of a protein’s structure (termed the “phase problem”), but resolution can be improved by multiwavelength anomalous diffraction (MAD) x-ray crystallography. MAD utilizes heavy atoms such as selenium and tellurium in proteins to enrich x-ray diffraction data. Additionally, selenium-77 can be incorporated to better understand enzyme structure and function by NMR spectroscopy. The low natural abundance of tryptophan (1.3%) and methionine (1.8%) make them important candidates for synthesis because of their minimal contribution to structural or catalytic activities. The utility of a selenium-containing tryptophan analog, β-selenolo[3,2-b]pyrrolyl-L-alanine ([4,5]SeTrp), has already been confirmed in the literature. Additional isomers of selenium-containing tryptophan analogs ([6,7]SeTrp), as well as tellurium-containing analogs ([6,7]TeTrp), will add to the toolbox of heavy atom amino acids for use in the elucidation of protein structure and function. The progress towards the synthesis of [6,7]SeTrp and [6,7]TeTrp will be presented.

Improving the synthesis of selenium- and tellurium-containing tryptophan amino acid analogs

2019 Spring National Meeting

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