Mastoparan B自黑腹虎頭蜂蜂毒液中分離出，是蜂毒液中最主要的組成分之一，由十四個胺基酸 (LKLKSIVSWAKKVL-NH2) 所組成，MP-B在水中的構形相當不穩定，而在TFE (三氟乙醇)水溶液中會形成穩定的兩性二級結構 (α螺旋)。然而，隨著溫度的改變，此時MP-B在構形上也發生變化；當高溫的狀態下，無規捲曲 ( random) 為主要結構形態。在此，我們對於溫度改變所產生構形的改變，以及胜肽分子動態行為感到興趣，因此我們希望透過圓二色光譜，核磁共振方法研究 MP-B 在 TFE 水溶液、 SDS 似膜環境中的動力學行為。而結構模擬與計算、擴散實驗 (diffusion) 及 13 Cα 弛緩實驗(relaxation) 得知 MP-B 摺疊過程，經實驗結果對於具芳香環殘基的色胺酸(tryptophan) 在 MP-B 中扮演的角色，也有進一步的討論。 Mastoparan-B(MP-B), is a tetradecapeptide isolated from the venom of the hornet Vespa basalis (LKLKSIVSWAKKVL-NH2).Structure of MP-B is random coil in aqueous solution and folded into an amphiphilic α-helix in the presence of TFE. However, as temperature increase, random coil structure is dominant. In this study, we are interest to insight into the structure transition of coil-helix as temperature varied. We investigate the structure, diffusion and dynamics of MP-B as temperature varied in aqueous TFE and SDS micelle by NMR and CD. The characteristic differences, which may imply the folding process of MP-B, are reported here. Role of tryptophan residue on stabilization of helical structure of MP-B is also characterized.
