關於抗菌胜肽結構與活性之間的關係已經被研究，有許多的結構參數表 明它們與活性之間具有關聯性。例如：極性角度與電荷對於胜肽的抗菌作用已 被證明是重要的。 MP-B 是本研究的模型胜肽，用來探討結構參數中包括：極性角度、電荷、 螺旋含量和疏水性與胜肽分子內的相互作用，我們提出新的結構參數為電荷密 度，討論陽離子氨基酸殘基的分佈對抗菌活性影響的效果，我們利用高解析的 二維核磁共振光譜觀察 MP-B 的構象變化與抗菌活性之間的關聯性，同時整理 先前的研究，並且分析胜肽結構參數對抗菌活性的影響。 胜肽的電荷集中 在 C 端時，電荷密度顯示出有一個較大的值，可能形成 較小的寡聚行為以及降低抗菌活性。同時我們在 RP-HPLC 滯留時間顯示，當 胜肽具有較小的極性角度時，疏水性與 RP-HPLC 的靜相相互作用力較強。而 另一方面，當胜肽具有較大的極性角度範圍時，若範圍內有更多電荷殘基與芳 香族殘基則顯示出與螺旋含量有著正相關。胜肽的屬性不是由特定的某個結構 參數所決定。這些胜肽的活性被認為是透過綜觀的結構參數所決定，並非是特 定的某個氨基酸殘基。 Relationship between structure and activity of the antimicrobial peptide has been reported in previous studies. Many structure parameters have been suggest to correlate with their activity. For example role of polar angle and charge for antibacterial have been demonstrated to be importance. MP-B, as a model peptide in this study, is used to explore the correlation of the structural parameters, including polar angle, charge, helix content and hydrophobicity with their intramolecular and antimicrobial activity by using high-resolution two-dimensional NMR spectroscopy, we investigate to the conformational change of MP-B and an analog and analysis the impact of these parameters on the antimicrobial activity. We investigate in detail the influence of the angle subtended by the positively charged amino acids on amphipathic helical peptides. The concentrated charge at C terminal, shows a larger value of the generalized order parameters relative to MP-B, and might form smaller oligomers and reduced antimicrobial activity. The reversed phase HPLC retention times showed that peptides with smaller polar angle have stronger interaction with the hydrophobic stationary phase. On the other hand, peptides with more charged residues and aromatic residues within a larger polar angle show a positive correlation with the content of helix content (%). Peptide property does not dominated by a specific structure parameter. The activity of these peptides is thought to be determined by global structural parameters rather than by a specific amino acid residue.
