Difference between revisions of "Part:BBa K3739082"

Revision as of 19:31, 21 October 2021

Aly01-his-hutH-FT

Histidine ammonia-lyase with a his-tag is involved in catalyzing the reaction of changing L-histidine into trans-urocanate. Aly01 is a signal peptile. The proteins labeled of tetracysteine motif tag (FlAsH tag, FT in short) can be detected with the biarsenical compound FlAsH.

Biology

FlAsH system was previously reported as a fluorescence detector for secreted proteins1. The protein labeled of tetracysteine motif tag (FlAsH tag, FT in short) can react with biarsenical compound FlAsH, showing great fluorescence at 528 nm emission. FlAsH system is used to quantify and qualify the secretion efficiency. Aly01 is a signal peptide, and we used Aly01-his-hutH-FT to verify the secretion effect of Aly01.

Usage

We ligased the induced promoter+RBS (BBa_K525998) and the parts (BBa_K3739082) on the expression vector pET-28a(+) by standard assembly (BBa_K3739084). Then the ligation mixture was transformed into E.coli BL21 (DE3), and the correct recombinant one was confirmed by kanamycin, colony PCR and sequencing.

Characterization

1. Agarose Gel Electrophoresis

After BBa_K3739084 was constructed on vector pET-28a(+) and transformed into E.coli BL21 (DE3), colony PCR was done to verify that the plasmid was correct. Data is shown below:

Fig. 1. Colony PCR results of BBa_K3739084

2. Qualification of LMT secretion efficiency

After cultivation for 5 hours at 37℃ and induction for 2 hours with 0.1mM IPTG, the cell supernatant was separated by centrifugation. The supernatant along with 2 μM FlAsH-EDT2 and 1 mM DTT were added to wells in a 96-well plate. Following incubation in the dark for 1 h at 37 °C, fluorescence was measured by 503 nm excitation and 528 nm emission, and each value was normalized by OD600.

Fig. 2. Fluorescence intensity/OD600 of cell supernatant after incubation in the dark for 1h. The result shows that the fluorescence intensity/OD600 of the group Aly01 and LMT is significantly higher than native control group, which proves that these 2 signal peptides can function well.

Reference

1. Haitjema, C. H.; Boock, J. T.; Natarajan, A.; Dominguez, M. A.; Gardner, J. G.; Keating, D. H.; Withers, S. T.; DeLisa, M. P., Universal Genetic Assay for Engineering Extracellular Protein Expression. ACS Synthetic Biology 2014, 3 (2), 74-82.

Sequence and Features