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| Modification of Mn Superoxide Dismutase Gene from Bacillus cereus M22 And Expression in Pichia pastoris |
| Yan Xu Qi Wang |
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Abstract As an excellent heterologous gene expression system, Pichia pastoris has been utilized wildely. According to the biased codes which are used by pichia pastoris, we optimized the gene of Mn-SOD which is from Bacillus cerues M22 and synthesize a new sequence on the premise of no modification of the amino acid sequence. A recombinant plasmid pPICZαA/Mn-SOD-2 was constructed and integrated into the genome of pichia pastoris GS115 by electroporation after linearization. The positive transformant was filtrated by zeocin resistance and PCR with specific primers. The recombinant Mn-SOD-2 protein was successfully expressed in Pichia pastoris based on the evidences that the obvious activity of SOD existed in Native-PAGE and a relative molecular weight about 24 kD appeard in SDS-PAGE as expected. The maximum activity of the recombinant with codons optimized reached 228 U/mL after being induced with 72h, which was nearly 3.2 times of the original strain. Additionally, the recombinant showed the upstanding expression stability.
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Received: 14 January 2008
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Corresponding Authors:
Qi Wang
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