The Design,Expression And Dynamics Simulation Of New Heterozygous Antimicrobial Peptides

Antibacterial peptide is a micromolecule peptide material created by organism. This antibacterial peptide has obvious killing impact on multiple microorganism, virus and even cancer cells. The antibacterial mechanism of antibacterial peptide is different from the antibacterial mechanism of antibiotic. The bacteria is not easy to have drug resistance against antibacterial peptide. Thus, antimicrobial peptide is most expected to become a new style antimicrobial drugs.Cecropins is a kind of antibacterial peptide which has be found earliest and studied mostly.It has many advantages, simple structure, wide antimicrobial spectrum,etc.But now the natural grain bacteriostatic effect of cecropins is not very ideal and need a certain distance to be improved when comparing with the general antibacterial drugs, which forced people to use molecule transforming or new designing to design a new antibacterial which have high antibacterial activity.In order to improve the antibacterial activity of the antibacterial peptide, this paper is designed to complete the following content:1. Firstly, used the gene engineering technology to heterozygosize the antibacterial peptides Cecropin B(CB) and antibacterial peptides Tmp1,and then designed and synthesized into two heterozygous antimicrobial peptides Ctp1and Ctp2. Secondly, used the bioinformatics methods to predicted their secondary structure, amphiphilic, electric field distribution and transmembrane area,ect. The prediction analysis showed that the secondary structure of antimicrobial peptides were mainly a-helix structure and had strong amphipathy. Besides, the heterozygous antibacterial peptides might have stronger antimicrobial activity than CB and Tmp1.2. Based on Escherich coli bias codons, translated the antibacterial peptideamino heterozygous acid sequences into DNA sequence. And then,1) divided their DNA sequences into7sections to become a overlap primer with18bp-20bp;2) used overlap PCR amplification way to synthetize genes complete sequence;3) introduced the restriction enzymes site Nde I and BamH I into both ends of genes complete sequences;4) connected the heterozygous antibacterial peptides with the plasmid pET lla to become recombinant plasmids and then transforme into E.coli JM109for expression. Used the Glycine-SDS-PAGE gel electrophoresis to appraise express products.3. Used the method of molecular dynamics to further analyse the structure and movement of the antimicrobial peptides. This analysis would provide more reliable theoretical basis for future design and analysis of the antimicrobial peptides. This experiment took heterozygous antimicrobial peptides CB and Ctp2as examples to proceed the simulation studies on the molecular dynamics. The final results showed that the angle between the two a-helixes of the antimicrobial peptide was close to right angle. After moving, the two a-helixes was almost in the same flat surface. The forms of its exercise was just like Cecropin B. Theoretically, Ctp2should have stronger antibacterial ability than CB.