Study On Small Molecule Cationic Antimicrobial Peptides Screening By Using Virtual Combinatorial Design And Its Bio-effects

For the strong resistance of antimicrobial drugs, especially the overuse of antibiotics, it isurgent to develope new antimicrobial drugs with high-efficiency,low-toxicity,no-residues.Because of the good stability, low side-effects, no-resistance,etc.,the antimicrobial peptides areexpected to overcome the current antimicrobial drugs series of problems.At present,a varietyof molecular design and modification methods were used to improve antimicrobial activityand to reduce its toxicity,which lay the foundation for the clinical application of antimicrobialpeptides.Although molecular modification of antimicrobial peptide has made encouragingprogress,antimicrobial peptides still have many problems in antimicrobial activity,chemicalsynthesis and cell toxicity.Based on the above research status, a new design concept of small cationic antimicrobialpeptides with short peptides chain,more charge,strong amphiphilic,more favorable amino acids,was proposed by using virtual combinatorial designs approach.The virtual combinatorialdesigns and high-throughput screening of antimicrobial peptides were performed by usingquantitative structure-activity relationship (QSAR) method based on the template cationicantimicrobial peptides LfcinB64-9(RRWQWR),and taking into account the sequencerequirements of antimicrobial peptides mode,the amino structure of the dominant sites.Thedetail as following,①to identify the mode sequence of cationic antimicrobial peptides basedon the antimicrobial peptides database(APD2)though the primary sequence alignment analysis;②to identify the favorable amino acids of the core sequence and the structure modificationmethods by using the QSAR method;③the virtual antimicrobial peptides library wereconstructed based on sequence mode,the dominant sites of amino acid and its structuremodification of the template LfcinB64-9;④the peptidomimetic screening based on thestructure-activity relationship analysis;⑤to synthesize,purify and identify peptidomimetic byusing Fmoc solid-phase synthetic,RP-HPLC and by MS,respectively;⑥to screen the perfectantimicrobial peptides through the antibacterial activity,cell toxicity and stability test to lay thefoundation of ext-medicine.The important research results as following:(1) a virtual combinatorial screening methodwere established for the small molecule cationic antimicrobial peptides;(2)three highly efficient cationic antimicrobial peptides with low-toxicity,low side-effects and no-resistancewere screened.The results show that the new design concept of "short peptides chain,morecharge,strong amphiphilic,more favorable amino acids" for small molecule of cationicantimicrobial peptides and virtual combinatorial designs approach can save time and reducecost for designs and screening new antimicrobial peptides;meanwhile,they can improve thereasonability and feasibility for antimicrobial peptides design.The three small moleculecationic antimicrobial peptides designed in this paper was expected to have good structurespecificity, strong anti-enzymatic ability, clear action mechanism, low-toxicity, potentialmedicines and easy to synthesize.In the all, the combination peptide libraries and molecular modeling method of screeningantimicrobial peptides, not only can reasonably design the diversity peptide molecules withhigh bio-activity,but also can improve effective to the screening, reduce research costs,andsolve the problem of scale production of antimicrobial peptides.The results of this paper hasimportant research value for the clinical application of antimicrobial peptides.