Recombinant production of medium- to large-sized peptides in Escherichia coli using a cleavable self-aggregating tag

Table 1 Protein quantitation

Target peptide	MW (kD)	Aggregate yield^a (μg/mg wet cell pellet)	Peptide yield^b (μg/mg wet cell pellet)	Cleavage efficiency^c (%)	Percent recovery^d (%)
pET-P-Intein-ELK16
GLP-1	3.5	31.1	1.8	60.9	46.8
IGF-1α^e	7.8	35.4	5.2	70.6	62.0
CCL5^e	7.8	35.5	5.2	70.9	61.3
SDF-1α^e	8.0	28.4	3.5	53.3	50.7
Leptin^e	16.2	44.6	10.5	60.3	60.3
pET-Trx-P-Intein-ELK16
Trx-GLP-1	16.9	52.4	9.7	57.4	46.2
Trx-IGF-1α	21.2	34.0	9.2	67.8	59.4
Trx-CCL5	21.2	57.8	7.0	44.8	26.5
Trx-SDF-1α	21.2	56.5	5.0	35.3	19.3
Trx-BNP	17.0	49.9	13.4	67.1	66.6
Trx-Ex-4	17.7	11.4	3.4	75.3	73.1

^aYield of protein aggregate
^bYield of free target peptide after intein-mediated cleavage from LB culture with wet cell weight of 2.66 ± 0.99 mg/mL, estimated by densitometry analysis software Quantity One
^cCleavage efficiency as calculated by dividing the amount of cleaved protein aggregate over that of the total aggregate before cleavage
^dPercent recovery in terms of mass as calculated by dividing the mass of the free peptide after cleavage over that could be theoretically obtained from the respective protein aggregate, assuming a complete cleavage and release
^eThe peptides were in the insoluble fraction after intein-mediated cleavage

ISSN: 1475-2859