Rapid and efficient production of cecropin A antibacterial peptide in Escherichia coli by fusion with a self-aggregating protein

Table 2 Quantification of cecropin A peptides cleaved from the fusions in the three different schemes

Expression systems	MW (kDa)	Fusions yield^a (μg/mg wet cell pellet)	Peptide yield^b (μg/mg wet cell pellet)	Cleavage effciency^c (%)	Percent recovery^d (%)	Peptide purity^e (%)
CF system	4.6	─	0.93^f	─	─	90.4
AT-HIS system	4.4	4.85	0.41	100	52.14	92.1
SA-ELK16 system	4.4	51.16	6.20	79.50	78.38	99.9

^aYield of fusion proteins in the form of aggregates or soluble fractions
^bYield of cecropin A peptides after intein-mediated cleavage in LB culture: 2.87 ± 0.62 mg/ml wet cell weight in the SA-ELK16 system and 1.48 ± 0.48 mg/ml wet cell weight in the AT-HIS system, estimated with the densitometric analysis software Gel-Pro Analyzer or BCA Protein Assay Kit
^cCleavage efficiency was calculated by dividing the amount of cleaved protein aggregate by the amount of total aggregate before cleavage
^dPercentage recovery of cecropin A peptide was calculated by dividing the mass of cecropin A peptide after cleavage by the mass that could be theoretically obtained from the fusion protein
^ePurity of CeA peptide was calculated with the BandScan software
^fYield of CeA peptide in the CF system was 0.93 μg/ml of reaction mixture

ISSN: 1472-6750