Cloning and Nucleotide Sequence Analysis of Complementary DNA Encoding Antimicrobial Peptide from Dung Beetle Larva

Abstract

The gene encoding antimicrobial peptide (AMP) was cloned from dung beetle larva. The DNA sequence analysis of the gene revealed that the cloned cDNA had 328 bp in length, and comprised of one open reading frame (ORF) encode for 80 amino acid residues, which had a predicted molecular weight of 8.55 kDa. The nucleotide identity analysis to a related AMP gene demonstrated that the identity values ranging between 15 to 96%. The most identity was the coprisin from Copris tripartitus (96%) follow by defensin A from Anomala cuprea (36%), defensing B from Anomala cuprea (30%), rhinoceros defensin from Oryctes rhinoceros (20%), and defensin-2 from Pediculus humanus corporis (15%). Antimicrobial activity testing of synthetic peptides derived from the deduced amino acid sequence indicated that it able to inhibit Escherichia coli, Pseudomonas aeruginosa, and Salmonella Typhimurium at the MIC of 7.8, 15.6 and 31.25 μg/ml respectively, whereas the MIC for Klebsiella pneumoniae, and Staphylococcus aureus were more than 500 μg/ml