Abstract:

The objective of this study was to determine the optimal induction conditions for the expression of hybrid
antimicrobial peptide MgJ in Pichia pastoris. The SacI-linearized recombinant expression vector pPICZαA-MgJ was
transformed into Pichia pastoris GS115 by electroporation. The positive clones were screened with Zeocin and identified
by PCR. The protein expression was induced by methanol and the expression conditions of hybrid antimicrobial peptide
MgJ were optimized. The results showed that the optimum expression conditions of MgJ were as follows: 28 ℃, 250 r/min,
adding 0.5% (V/V) methanol to the culture every 24 h, and induced expression time 120 h. The amount of expressed MgJ
could reach up to 11.9 mg/L. After purification, the expressed product MgJ had better antimicrobial activity on S. aureus
ATCC 29213 with a minimal inhibitory concentration (MIC) of 10 μg/mL.

Key words: hybrid antimicrobial peptide MgJ, Pichia pastoris, optimization of expression conditions