title: Cecropin A-melittin mutant with improved proteolytic stability and enhanced antimicrobial activity against bacteria and fungi associated with gastroenteritis in vitro.
abstract: Cecropin A-melittin (CAM), a chimeric antimicrobial peptide with potent antimicrobial activity, is threatened by some special extracellular proteases when used to deal with certain drug-resistant pathogenic microbes in the gastrointestinal tract. Thus, a four-tryptophan-substitution mutant (CAM-W) from CAM was developed via the replacement of special amino acid residues to enhance the antimicrobial potency and to improve the proteolytic stability of this agent. The pharmaceutical index of CAM-W was investigated, with a focus on biological potency, cytotoxicity, and proteolytic stability, as well as pH and thermal resistance. CAM-W exhibited potent antimicrobial activity and was approximately 3-12 times higher than that of CAM. CAM-W also exhibited a strong antifungal activity against a series of common pathogenic fungi, in a lower IC50 range between 2.1mg/L and 3.3mg/L than that of its reference CAM ranging from 9.8mg/L to 14.2mg/L. Besides, CAM-W showed moderate cytotoxicity (IC50>300mg/L) in erythrocyte lysis test. In addition, CAM-W overcame challenges under various conditions, including specific temperatures (20, 30, 40, 50, 60, 70, 80, and 90°C), pH values (2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, and 9.0), and proteases (trypsin, pepsin, human neutrophil elastase, Pseudomonas aeruginosa elastase, and Staphylococcus aureus V8 protease) that are commonly present in human gastrointestinal tract. These results suggest that the four-tryptophan-substitution can confer CAM-W with a high pharmaceutical index, which is important for CAM-W to become a potential alternative to conventional antibiotics against bacteria and fungi associated with gastroenteritis.
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, 22 Xinong Road, Yangling 712100, Shaanxi, PR China.
authors.forename: Shengyue
authors.initials: S
authors.lastname: Ji
authors.affiliation: Beijing S&V Science and Technology Co., Ltd., Beijing 102200, Beijing, PR China.
authors.forename: Weili
authors.initials: W
authors.lastname: Li
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, 22 Xinong Road, Yangling 712100, Shaanxi, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, 22 Xinong Road, Yangling 712100, Shaanxi, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, 22 Xinong Road, Yangling 712100, Shaanxi, PR China. Electronic address: jiziqing2010@163.com.
authors.forename: Binyun
authors.initials: B
authors.lastname: Cao
mesh_terms: D000890:Anti-Infective Agents; D000935:Antifungal Agents / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000235:genetics*; D001419:Bacteria / Q000187:drug effects; D004355:Drug Stability; D005658:Fungi / Q000187:drug effects; D005759:Gastroenteritis / Q000188:drug therapy / Q000382:microbiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008555:Melitten / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D010447:Peptide Hydrolases; D059748:Proteolysis; D013696:Temperature
chemical_list: D000890:Anti-Infective Agents; D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D008555:Melitten; C031161:cecropin A; D010447:Peptide Hydrolases
keywords: Antimicrobial peptide; Biological potency; Pharmaceutical index; Proteolytic stability