Part:BBa_K354001:Design
PlcR-PapR - Gram+ve Quorum Peptide
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Design Notes
The sequence recognised by the SecA pathway had to be included in the synthesised sequence so as to ensure that the fusion peptide is adequately exported fro the cell. A ribozyme binding site (RBS) was also included in the final sequence. Furthermore, the sequence was codon optimized for Lactobacillus gasseri.
Source
This sequence was adapted from the naturally-occurring fusion peptide found in the Bacillus cereus genome.
Safety
This fusion peptide directly upregulates gene expression when it binds to its cognate promoter. It has been suggested that this peptide can activate expression of 20 different genes.
The synthetic fusion peptide is also expected to be much more effective at increasing gene expression than the natural quorum peptides it is derived from. There are several safety issues regarding this Biobrick:
Firstly the quorum peptide we have selected activates virulence in Bacillus thuriengiensis and Bacillus anthracis. B.thuriengiensis is a soil bacterium which is pathogenic to insects and B.anthracis is a human pathogen. It is possible that unintended exposure to our enhanced quorum peptide could increase virulence in these organisms.
It is also possible that the peptide could activate gene expression by binding to promoters other than the one we intended it to, causing off target effects.
References
[1] Slamti L. & Lereclus D. (2002), A cell-cell signaling peptide activates the PlcR virulence regulon in bacteria of the Bacillus cereus group. The European Molecular Biology Organisation Journal 21: 4550-4559.
[2] Pomerantsev A.P., Pomerantseva O.M. & Leppla S.H. (2004), A Spontaneous Translational Fusion of Bacillus cereus PlcR and PapR Activates Transcription of PlcR-Dependant Genes in Bacillus anthracis via Binding with a Specific Palindromic Sequence. Infection and Immunity 72:5814-5823.
[3] Optimizer, http://genomes.urv.es/OPTIMIZER/, Last accessed September 29, 2010 [4] Marco Weinberg, PhD. Antiviral Gene Therapy Research Unit, Department of Molecular Medicine and Haematology, University of the Witwatersrand Medical School, 7 York Rd. Parktown 2193 SOUTH AFRICA, marc.weinberg@wits.ac.za.