抗菌胜肽擁有廣效的抗菌活性，像是對抗細菌、真菌及病毒等，其抗菌活性與結構參數擁有密切的關係。但是目前並無明確表示結構參數與抗菌活性之關係，因為當置換胺基酸時，不僅改變疏水性或電荷，可能也改變疏水力矩、極性角度和螺旋。所以本研究將MPB及其衍生物的結構參數與抗菌活性之關係進行統計歸納，探討彼此間的關係，另外設計MPB-W13，以改變疏水性為重點，增加胜肽尾端的疏水性，並期望能增加π-π interaction，使尾端更穩定，且增加抗菌活性。 根據所進行的MPB-W13實驗之結果與MPB及其衍生物的結構參數與抗菌活性之關係，本研究驗證了以下幾點結構參數與抗菌活性之關係：（1）抗菌胜肽的疏水性大，抗菌效果較好，而N端與C端的疏水性也與抗菌活性有關係，當疏水性愈大，抗菌效果較佳，但是疏水性太大可能影響到抗菌胜肽聚集行為，導致長時間抗菌效果較差，（2）置換的胺基酸會影響抗菌胜肽的兩親性，其中發現兩親性的疏水區域愈大，抗菌效果愈好，而親水區域愈大，抗菌效果愈差。 另外，從MPB-W13的最佳化結構中，我們發現到W9和W13的芳香環側鏈並未形成π-π interaction，但是MPB-W13的螺旋含量最高。可能由於W13與L14之間的疏水作用，影響螺旋結構的穩定，並可能進而導致抗菌活性受到影響。 Most antimicrobial peptides show a wide spectrum of activity against bacteria, fungi and viruses. Their structural parameters are closely related with antimicrobial activity. However, the relationship between structural parameters and antimicrobial activity is still not vary clear. This research explored the relationship between structural parameters and antimicrobial activity of MPB and its analogues. We designed MPB-W13 (LKLKSIVSWAKKWL-NH2) to increase the hydrophobicity and expected to add a π-π interaction that may make the C terminal more stable to increase antimicrobial activity. According to the results of MPB-W13 and the relationship between structural parameters and antimicrobial activity of MPB and its analogues, the following results were obtained: (1) The higher overall hydrophobicity of antimicrobial peptides may increase antimicrobial activity, but an optimized hydrophobicity is exist. The N-local hydrophobicity and the C-local hydrophobicity are also closely related with antimicrobial activity. The higher local hydrophobicity may increase the antimicrobial activity. (2) The substituted amino acid may affect the amphiphilicity. We found a larger hydrophobic region in amphiphilicity increase antimicrobial activity and a larger hydrophilic region in amphiphilicity decrease antimicrobial activity. Additionally, we didn’t find the π-π interaction between W9 and W13. However, the experimental results showed W13 could have hydrophobic interaction with L14. It revealed that the 13th amino acid may affect the structural stability of C terminal of MPB-W13 and led antimicrobial activity to change.
