Significant Expansion of the Fluorescent Protein Chromophore through the Genetic Incorporation of a Metal-Chelating Unnatural Amino Acid

Authors

  • Xiaohong Liu,

    1. Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)
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    • These authors contributed equally to this work.

  • Jiasong Li,

    1. Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)
    2. School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026 (China)
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    • These authors contributed equally to this work.

  • Cheng Hu,

    1. Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)
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  • Qing Zhou,

    1. Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)
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  • Wei Zhang,

    1. Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)
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  • Meirong Hu,

    1. Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)
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  • Juanzuo Zhou,

    1. Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)
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  • Jiangyun Wang

    Corresponding author
    1. Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)
    • Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)
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  • We gratefully acknowledge the Major State Basic Research Program of China (2010CB912301, 2009CB825505), National Science Foundation of China (90913022, 31100616, 31270859) to J.W. and X. H. Liu. We thank Z. Xie and P. Wu for help with protein mass spectrometry and Y. Wang in fluorescence determination, and Dr. S. Perrett for comments on the manuscript.

Abstract

original image

Caught red-shifted: A novel metal-chelating unnatural amino acid with an 8-hydroxyquinoline group (HqAla) can be enzymatically incorporated into GFP (see scheme). Substituting a Tyr residue in the chromophore of FPs with HqAla results in significantly red-shifted excitation and emission maxima. The crystal structure of superfolder GFP bearing HqAla in its chromophore shows the structural basis for these red shifts.

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