Translational_Unit
Part:BBa_K2278022
Designed by: Paul ZANONI Group: iGEM17_INSA-UPS_France (2017-10-08)
Lecrocin I antimicrobial peptide with Alpha-Factor Secretion Signal
Sequence and Features
Assembly Compatibility:
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21INCOMPATIBLE WITH RFC[21]Illegal XhoI site found at 244
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Introduction
This DNA biobrick was designed in order to produce Lecrocin I AMP in a yeast organism strain.
1- Biological background
Mechanisme Antimicrobial peptides are phylogenitically ancient components of innate defense mechanisms of both invertebrates and vertebrates. In the context of growing prevalence of antibiotic-resistance of bacterial strain, the AMP can be considered as potential new therapeutical candidates. Leucrocin I from Siamese crocodile white blood cells shows a good antibacterial activity towards Vibrio cholerae. The peptide is a 7 amino acid residue : NGVQPKY with a molecular mass around 806.99 Da. The mechanism of action of the Leucrocin I has been observed with fluorescence and electron microscopy This cationic molecules and can target bacterium membranes, to create pores in it, leading to the lysis of the cells.2- Usage in iGEM projects
The part was designed to constitutively produce the leucrocin I AMP with a yeast promoter. The α-factor (BBa_K1800001) sequence contains a RBS and a signal sequence to secrete the produced peptides.Experiments
1- Molecular biology
The gene was placed in silico under the control of an alpha factor signal. IDT performed the DNA synthesis and delivered the part as gBlock. The construct was cloned by conventional ligation into pSB1C3 plasmid The construction was then inserted on plasmid pPICZa and integrated in the yeast genome.
Analysis of the restriction mapSequencing
The sequencing successfully validated the sequence of the biobrick.2- Expression in vivo
Integration in Pichia pastori genome
Protocole
The biobrick was placed in silico under the control of p(GAP) promoter (BBa_K431009) and was cloned in pPICZalpha vector, a good expression vector for Pichia pastoris. The plasmid was then linearized and transferred in Pichia pastoris by electroporation. The integration is predicted to be at the p(GAP) location. Indeed, the p(GAP) promoter makes genome recombination easier in Pichia pastoris genome thanks to its homology site.Expression of Leucrocin I AMP
Leucrocin I production was performed with the P. pastoris in YPD (40 g/L glucose) and grown for 4 days at 30 °C in an agitating incubator. 15mL of each supernatant culture were stored at 4°C while 35mL were freeze-dried and then resuspended in 3.5mL of water.Characterization
Toxicity assay
The engineered yeast were used in a halo assay against V. harveyi as the target of AMPs. A paper soacked with a yeast solution was placed on the plate and V. harveyi growth in the viscinity of the yeast patch was followed. The toxicity assay did not reveal any activity of the Leucrocin I AMP
[edit]
Categories
Parameters
None |