Part:BBa_K3386003

EGFP is a reporter protein

Usage and Biology

EGFP (enhanced green fluorescence protein) is a green fluorescent protein reengineered in 1996, originally derived from Aequorea victoria. Since wild-type GFP had low fluorescent intensity when excited by blue light at 470 nm, the sequence was re-engineered in order to increase the sensitivity of this reporter [1].

Characterization

The fluorescence of EGFP was compared with commercially available superfolder GFP (sfGFP) (Adgene) [2]. We transformed TOP10 cells with a plasmid containing egfp or sfgfp under an inducible pMphR promoter (BBa_K3386002). Chloramphenicol resistance gene was the selection marker. The backbone used for assembly of the genetic circuit was pSB1C3. The cells were grown for 20 h in LB with chloramphenicol in absence of MphR repressor protein. The fluorescence and optical density were measured in 15 min intervals. All fluorescence values were normalized with optical density. The fluorescence emitted by this reporter in Escherichia coli seems to be much lower than sfGFP (Fig. 1).

Figure 1. Comparison of fluorescence produced by cells transformed with a plasmid expressing sfGFP or EGFP emitted by sfGFP and EGFP. OD - optical density. The graph shows the data from a single measurement.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  INCOMPATIBLE WITH RFC[1000]

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