Difference between revisions of "Part:BBa K137058"

Latest revision as of 08:57, 13 October 2014

GFP fimE switch with 250 bp tetR promoter

A promoter facing upstream is flanked by two FimE binding sites. GFP is downstream to this fimE switch. Active FimE will flip the promoter such that GFP is expresssed.

Usage and Biology

The series K137057-K137062 were placed in pSB4K5 and cotransformed with pFIP¹. Using the Caltech iGEM [http://2008.igem.org/Team:Caltech/Protocols/FimE FimE assay], the series of parts produced the following fluorescence values:

Error bars show the standard deviation of experiments performed in triplicate.

Maximum fluorescence was observed to occur at about a separation length of 250 bp. This distance may be a function of entropy and enthalpy. The chances that two DNA segments on the same strand come together statistically decrease as the two segments are separated by intervening sequences. In addition, two sites very close together are unlikely to come into contact with each other, as it is energetically unfavorable to bend DNA to such a great degree. These two opposing forces might explain the presence of an optimal separation length.

1. Ham TS, Lee SK, Keasling JD, and Arkin AP. A tightly regulated inducible expression system utilizing the fim inversion recombination switch. Biotechnol Bioeng 2006 May 5; 94(1) 1-4.

Sequence and Features</>