Disrupting Fluorescence by Mutagenesis in a Green Fluorescent Fatty Acid Binding Protein from a Marine Eel

Protein J. 2020 Apr;39(2):145-151. doi: 10.1007/s10930-020-09883-3.


Biofluorescence has been found to be an increasingly widespread phenomenon in the ocean. The reclusive Caribbean chlopsid eel, Kaupichthys hyoproroides displays bright green fluorescence in its native marine environment. We have previously shown the fluorescence to be attributed to a fluorescent fatty acid-binding protein, Chlopsid FP, part of a larger family of fluorescent fatty acid-binding proteins, including the homologous UnaG. All require the addition of exogenous bilirubin for fluorescence. Here, we report the generation of a series of point mutants, and deletions that result in the quenching of fluorescence in Chlopsid FP. In addition, we report the binding constants of bilirubin to Chlopsid FP and mutants, measured by fluorescence titration. This study provides key insights into the potential mechanism of fluorescence in this class of fluorescent fatty acid-binding proteins.

Keywords: Bilirubin; Chlopsid FP; Eel; Fatty acid-binding proteins; Green fluorescence.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bilirubin / metabolism*
  • Eels*
  • Fatty Acid-Binding Proteins / genetics*
  • Fatty Acid-Binding Proteins / metabolism
  • Fluorescence*
  • Luminescent Proteins / genetics*
  • Protein Binding
  • Sequence Deletion


  • Fatty Acid-Binding Proteins
  • Luminescent Proteins
  • Bilirubin