Angewandte Chemie International Edition
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Inside Back Cover: Significant Expansion of the Fluorescent Protein Chromophore through the Genetic Incorporation of a Metal-Chelating Unnatural Amino Acid (Angew. Chem. Int. Ed. 18/2013)
A metal-chelating unnatural amino acid (UAA) with an 8-hydroxyquinoline functional group (HqAla) was enzymatically synthesized in one step. In their Communication on page 4805 ff., J. Y. Wang and co-workers show that incorporation of HqAla into fluorescent proteins shifts their emission maxima toward higher wavelengths (red-shifted). This UAA could be applied to engineering metalloproteins and brighter fluorescent proteins, as well as paramagnetic protein NMR spectroscopy.