Revision as of 13:23, 10 October 2018

sfGFP_optimism measurement device

It is a measurement device for sfGFP fluorescence intensity, which is composed of promoter (BBa_J23104), RBS (BBa_B0034), sfGFP (BBa_K2541400) and terminator (BBa_B0015).

Biology and Usage

Green fluorescent protein (GFP) offers efficient ways of visualizing promoter activity and protein localization in vivo, and many different variants are currently available to study bacterial cell biology. It exhibits intrinsic fluorescence and is commonly used as a reporter gene in intact cells and organisms [1]. Many mutants of the protein with either modified spectral properties, increased fluorescence intensity, or improved folding properties have been reported [2].

GFP often misfold when expressed as fusions with other proteins, while a robustly folded version of GFP, called superfolder GFP, was developed and described by Pédelacq et al at 2006 [3]that folds well even when fused to poorly folded polypeptides. Furthermore, sfGFP might be particularly suitable for gene expression studies, since the emergence of fluorescence closely matches induction of transcription. The superfolder GFP had been registered in iGEM BBa_I746916. Its codon usage is a compromise for optimum expression in E. coli and B. subtilis. There is another superfolder GFP designed by Overkamp W et al at 2013[4], which is codon optimized for S. pneumoniae. It was be used in Escherichia coli by Segall-Shapiro T H et al at 2018[5].

This year our team registered the superfolder GFP designed by Overkamp W et al with a BBa_K2541400 (called sfGFP). Compared to superfolder GFP(BBa_I746916), sfGFP (BBa_K2541400) is BbsI restriction site free, so it can be used in GoldenGate assembly to achieve efficient and rapid assembly of gene fragments. And sfGFP (BBa_K2541400) has stronger fluorescence intensity than superfolder GFP(BBa_I746916).

Characterization

The improved sfGFP (K2541400) variant was standardised into BioBrick format and its fluorescence intensity was compared with superfolder GFP(BBa_I746916) .Its x fold increased fluorescence intensity is a very useful feature. And it is BbsI restriction site free, so it can be used in GoldenGate assembly to achieve efficient and rapid assembly of gene fragments.

The new variant sfGFP (K2541400) was contributed to the Registry of Standard Biological Parts and it will be more widely used in the synthetic biology community.

Sequence and Features