J Biomed Res.  2013 Dec;14(4):235-239.

Characterization of two antimicrobial peptides identified from a random peptide library and expressed in the methylotrophic yeast pichia pastoris

• Jeon IS
• Song KD
• Oh JD
• Choi JK

Abstract

Antimicrobial peptides (AMPs) are an important component of innate defense mechanisms with broad-spectrum activities against various pathogenic microorganisms, including Gram-positive and Gram-negative bacteria, fungi, and viruses. Antibiotic resistance has become a pervasive and global health burden, resulting in the immediate need to develop a new class of antibiotic substances. We screened a 16-mer random peptide library using the yeast two-hybrid system with Beclin 1 as bait and found that two 16-mer peptides (named P4 and P30) appeared to interact with Beclin1 in the beta-gal assay. The two candidate cDNAs were introduced into the yeast secretory system of Pichia pastoris and their expression induced in the presence of methanol. Spectrophotometric analysis and Disc clear zone assay using the supernatant of the yeast growth media showed that both of the two peptides had strong activities against Staphylococcus aureus, MRSA (methicillin resistance Staphylococcus aureus), MRSA2242, and MRSA-2250, but no effect on commensal Lactobacillus strains. PCR analysis of the genomic DNA of transformed Pichia pastoris using AOX1 primers revealed that the two cDNAs were integrated into the genome at the AOX1 locus. Our result suggests that these peptides could be developed as a useful alternative to classic chemical antibiotics.

Keyword

antimicrobial peptide; Staphylococcus aureus; MRSA; Lactobacillus casei; Pichia pastoris

MeSH Terms

Anti-Bacterial Agents
Defense Mechanisms
DNA
DNA, Complementary
Drug Resistance, Microbial
Fungi
Genome
Gram-Negative Bacteria
Lactobacillus
Lactobacillus casei
Methanol
Methicillin-Resistant Staphylococcus aureus
Peptide Library*
Peptides*
Pichia*
Polymerase Chain Reaction
Staphylococcus
Staphylococcus aureus
Two-Hybrid System Techniques
Yeasts*
Anti-Bacterial Agents
DNA
DNA, Complementary
Methanol
Peptide Library
Peptides