Team:NCTU Formosa/Wet Lab/Expression

To ensure our target genes were successfully cloned into the pSB1C3 backbone, we ran the electrophoresis of Taq PCR products to check the sizes of the insert genes.

All of the sequences contained T7 promoter, RBS, bacteriocin, intein and CBD, were shown in Figure 1.

Figure 1: Our BioBrick design

After amplification with PCR, all the PCR products length around 1200 b.p. The exact lengths are listed in Table 1.

Table 1: The DNA length of each Biobrick
Bacteriocin	Length	Length of PCR product
Leucocyclicin Q	186 b.p.	1230 b.p.
Enterocin B	210 b.p.	1254 b.p.
Enterocin 96	219 b.p.	1263 b.p.
Lacticin Z	153 b.p.	1197 b.p.
Bovicin HJ50	171 b.p.	1215 b.p.
Durancin TW-49M	213 b.p.	1257 b.p.

Electrophoresis results of the PCR products with marker on the left side and target gene on the right side. The lengths are labeled beside each band.

Figure 2: Agarose gel electrophoretic pattern of taq PCR products of six bacteriocin genes containing T7 promotor, RBS, intein, and CBD: (A) Leucocyclicin Q (BBa_K2599014, 1230 b.p.) (B) Enterocin B (BBa_K2599011, 1166 b.p.) (C) Bovicin HJ50 (BBa_K2599009, 1125 b.p.) (D) Enterocin 96 (BBa_K2599012, 1175 b.p.) (E) Lacticin Z (BBa_K2599013, 1112 b.p.) (F) Durancin TW-49M (BBa_K2599015, 1169b.p.)

Protein Expression

After the expression from E. coli ER2566, we have to check whether the proteins are successfully expressed. We sonicate E. coli and run SDS-PAGE to make sure the correct sizes. The mass of each proteins are in Table 2.

Table 2. Mass of peptides with intein(kDa).
Bacteriocin	Mass (kDa)	Mass of peptides with intein
Leucocyclicin Q	6.4	34.4
Enterocin B	7.5	35.5
Bovicin HJ50	6.25	34.25
Enterocin 96	7.9	35.9
Lacticin Z	5.9	33.9
Durancin TW-49M	7.3	35.3

The gel of SDS-PAGE result are shown below. The mass of intein-CBD tag is 28 kDa, therefore, all the result shows the initial mass of each bacteriocin plus the mass of intein-CBD tag. From each SDS-PAGE result, we can confirm the production of target peptides.

Figure 3: SDS-PAGE electrophoresis of bacteriocin samples. M: protein Ladder 5–245 kDa, C: negative control (only intein+CBD ,28 kDa), EA: Leucocyclicin Q + intein + CBD (BBa_K2599014, 34.4kDa) EB: Enterocin B + intein + CBD (BBa_K2599011, 35.5 kDa) EC: Bovicin HJ50 + intein + CBD (BBa_K2599009, 34.25 kDa) ED: Enterocin 96 + intein + CBD (BBa_K2599012, 35.9 kDa) EE: Lacticin Z + intein + CBD (BBa_K2599013, 33.9 kDa) EF:Durancin + intein + CBD(BBa_K2599015, 35.3kDa)

Template