Rapidly maturing red fluorescent protein variants with strongly enhanced brightness in bacteria

FEBS Lett. 2003 Sep 25;552(2-3):110-4. doi: 10.1016/s0014-5793(03)00856-1.


A rapidly maturing variant of the red fluorescent protein DsRed was optimized for bacterial expression by random mutagenesis. The brightest variant contains six mutations, two of which (S4T and a silent mutation in codon 2) explain most of the fluorescence enhancement. The novel variants are expressed at 9-60-fold higher levels in Escherichia coli compared to DsRed.T3, but are not superior fluorophores on a per molecule basis. In contrast to previously available DsRed variants, DsRed.T3_S4T is sufficiently bright to monitor Salmonella gene expression in infected animals using flow cytometry. However, no fluorescence enhancement was observed in Leishmania or HeLa cells, indicating that these novel variants are specifically useful for bacteria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • DNA, Recombinant / genetics
  • Escherichia coli / genetics*
  • Female
  • Fluorescence
  • Genetic Variation
  • HeLa Cells
  • Humans
  • Leishmania mexicana / genetics
  • Luminescent Proteins / chemistry
  • Luminescent Proteins / genetics*
  • Luminescent Proteins / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Microscopy, Confocal
  • Mutagenesis
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Salmonella / genetics


  • DNA, Recombinant
  • Luminescent Proteins
  • Recombinant Proteins
  • red fluorescent protein