Lactose/IPTG inducible promoter with GFP reporter tagged with DAS-ssrA degradation tag followed by terminator. The tagged GFP is actively degraded within cell, thus provides better temporal resolution of green fluorescence and promoter activity. Presence of SspB is crucial for effective protein degradation.
Part was assembled using BrickClip assembly (BBF RFC104) using other biobrick parts as templates. BrickClip assembly is a special case of more general Paperclip assembly method.[1]
RBS (Elowitz 1999) -- defines RBS efficiency
Varies from -6 to +1 region from original sequence to accomodate BioBricks suffix. No secondary structures are formed in the given RBS region. Users should check for secondary structures induced in the RBS by upstream and downstream elements in the +50 to -50 region, as such structures will greatly affect the strength of the RBS. Contact info for this part: Brian Chow
Vinay S Mahajan, Voichita D. Marinescu, Brian Chow, Alexander D Wissner-Gross and Peter Carr IAP, 2003.
The Plac insert was PCR'd from the MG1655 strain of E.coli K12.
Inverting regulatory region controlled by LacI (<bb_part>BBa_C0010</bb_part>, <bb_part>BBa_C0011</bb_part>, etc.) The pLac regulatory region is a 243 base-pair sequence with standard BioBrick prefix and suffix sections on its ends. It contains two protein binding sites: CAP, which is generally present in E.coli and is assocciated with cell health and availability of glucose., and LacI, the Lac inhibitor <bb_part>BBa_C0010</bb_part> which binds in an dimerized cooperative manner to inhibit the transcription of the protein that follows. In the presence of lactose or IPTG, an analog of lactose, LacI is unable to correctly bind and inhibit transcription. This allows <bb_part>BBa_R0010</bb_part> to be used as a inverter or as a detector of lactose or IPTG.
LacI binds to this regulator. This part is incompatible with species containing active LacI coding regions. Lactose and IPTG disable the operation of LacI and this regulator. This part is incompatible with environments containing lactose or lactose analogs.
Double terminator consisting of BBa_B0010 and BBa_B0012
GFP (mut3b) with DAS-ssrA degradation tag
GFP comes from part BBa_E0040, the tag sequence was obtained from part BBa_M0052.
GFP (mut3b) (see part BBa_E0040) with added DAS-ssrA degradation tag (see part BBa_M0052). The tag increases GFP turn-over rate, thus providing better temporal resolution of green fluorescence. In the same time, maximal fluorescence amplitudes will be lower as newly formed protein is degraded as soon as it is formed. SsrA tags encode peptide sequence that is recognized by ClpA and ClpX unfoldases and ClpX mediator SspB.[1] ClpA and ClpX then form a proteosome-like complex with ClpP protease and the protein is degraded.[1] The final three residues of the tag determines the strength of interaction with ClpX and thus the final protein degradation rate.[2] The DAS tag encodes peptide sequence AANDENYADAS is reported to have low affinity to ClpX thus its mediated degradation very much depends on the concentration of SspB (ClpX mediator).[1] However, be aware that exact protein degradation rate is influenced by multiple other factors: ClpXP and ClpAP protease concentrations, protein stability, Km of binding to the protease, temperature [3]. ===References=== [1] Flynn, J. M. et al. Overlapping recognition determinants within the ssrA degradation tag allow modulation of proteolysis. Proc. Natl. Acad. Sci. U. S. A. 98, 10584???9 (2001). [2] Andersen, J. B. et al. New unstable variants of green fluorescent protein for studies of transient gene expression in bacteria. Appl. Environ. Microbiol. 64, 2240???6 (1998). [3] Purcell, O., Grierson, C. S., Bernardo, M. Di & Savery, N. J. Temperature dependence of ssrA-tag mediated protein degradation. J. Biol. Eng. 6, 10 (2012).
The tag was attached to GFP using PCR and MABEL (mutagenesis with blunt-end ligation), thus avoiding introduction of additional residues and restriction site. Different parts of the tag are recognized by different proteins, for example, the final 3 residues (DAS in this case) are recognized by ClpX, whereas first 4 residues of the tag are required for efficient SspB binding.[1] Thus modifications of these critical residues alter the efficacy with what different proteases bind to it.
Derived from the TE terminator of T7 bacteriophage between Genes 1.3 and 1.4 <genbank>V01146</genbank>.
Transcription terminator for the E.coli RNA polymerase.
Suggested by Sri Kosuri and Drew Endy as a high efficiency terminator. The 5' end cutoff was placed immediately after the TAA stop codon and the 3' end cutoff was placed just prior to the RBS of Gene 1.4 (before AAGGAG). Use anywhere transcription should be stopped when the gene of interest is upstream of this terminator.
Transcriptional terminator consisting of a 64 bp stem-loop.
Conversion of the iGEM parts registry to SBOL2.1