Part:BBa_K3041016
PLac-suckerin-9
Coding gene of Suckerin-9 of the Dosidicus gigas (Humboldt squid) codon-optimized for production in E. coli (BBa_K3041001) under control of the Lac expression cassette (BBa_K314103)
Validation
The successfully synthesized suckerins, codon-optimized for E.coli, were PCR amplified using the standard biobrick primers. In Figure 1, the PCR products of these specific suckerins were visualised on agarose gel. Suckerin-9, shows a clear band around 568bp.
Figure 1: Amplified suckerin genes 8, 9 and 12.
Polymerase chain reaction (PCR) products amplified with general prefix and suffix primers, shown by gel electrophoresis. Lane 1: 1kb ladder. PCR product at different concentrations of suckerin-8 (408 bp, lane 2 and 3), suckerin-9 (568 bp, lane 4 and 5), and suckerin-12 (696 bp, lane 6 and 7). The gel confirms the amplification of the desired suckerin proteins.
The corrected genes were inserted in the pBS1A3 plasmid. After successful transformation, colonies were selected and stored in liquid stock. After checking the plasmids, the PLac expression cassette was placed in front of the suckerin genes. These constructs were checked by PCR with standard biobrick primers, placed on an agarose gel and transformed into E. coli. The agarose gel in Figure 6 shows the fragments of all three different suckerins together with the Lac promoter. The bands of suckerin-12 are very faint, still, we decided to continue the transformation(fig. 2).
Figure 2: PCR of Plac-suckerin genes for plasmid validation. Lane 1: 1kb ladder, Lane 2+3: PLac-suckerin-8, lane 4+5: PLac-suckerin-9, lane 6+7: PLac-suckerin-12
E.coli DH5a colonies expressing the suckerins on pBS1A3 plasmids under the Lac promoter were successfully obtained, resulting in the construct pBS1A3-PLac-suckerine-9. These strains were used for initial protein production. Small scale 100 ml flask cultures were induced at an OD600 of 0.6-0.8 with 1 mM IPTG. After harvesting, the proteins were purified using the inclusion body purification protocol since these constructs did not contain a His6-tag. Figure 3 visualizes the successful production of the three suckerin types on SDS-PAGE. Note, the protein mixture obtained by the protocol was not dialyzed, resulting in an impure product(Fig. 3).
Figure 3: On SDS-PAGE gel there is visible suckerin protein purified from E. coli, for each of the different suckerin proteins. Lane 1: ladder, suckerin-12 (25 kDa, lane 3), suckerin-9 (21 kDa, lane 4) and suckerin-8 (20 kDa, lane 5).
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21INCOMPATIBLE WITH RFC[21]Illegal BglII site found at 2173
- 23COMPATIBLE WITH RFC[23]
- 25INCOMPATIBLE WITH RFC[25]Illegal NgoMIV site found at 126
- 1000COMPATIBLE WITH RFC[1000]
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