Mastoparan-B (MPB)是由臺灣胡蜂Vespa basalis毒液中發現分離出的一種胜月太，由十四個胺基酸組成，具有雙向性。其一級結構為：
H-Leu-Lys-Leu-Lys-Ser-Ile-Val-Ser-Trp-Ala-Lys-Lys-Val-Leu-NH2
於水溶液中，MPB並沒有固定的構形存在，然當於triflouroethanol (TFE)加入下（20-60%TFE），會以螺旋結構存在。在適量的TFE/H2O下，螺旋結構會安定的存在。因此利用二維核磁共振技術，結合電腦模擬計算，可以求得MPB於此環境下的結構。
由二維NOESY光譜上NOE的相對強度，作為結構計算之距離設限，利用距離幾何運算、設限分子動態模擬運算、結合距離幾何－動態模擬粹熄運算等不同的計算方法，所得的MPB之NMR結構皆位於同一個結構空間附近。十四個殘基中，N-端的兩個殘基極為鬆散，殘基3-14具有螺旋結構，支鏈原子的重疊度較骨架原子差。這些NMR結構都能表現MPB所具有的雙向性螺旋結構。於殘基3-14的螺旋結構中，親水性殘基形成親水性面，Lys4、Ser8、Lys11、Lys12位於此面，Ser5約位於親水面及疏水面交界；疏水性殘基Leu3、Ile6、Trp9、Ala10、Val13、Leu14，形成疏水性面；殘基Val7則位於親水面。

Mastoparan B(MPB), is a tetradecapeptide toxin islated from the venom of the hornet (Vespa basalis) which is the most dangerous species of wasps found in Taiwan. The primary structure of mastoparan Bis H-Leu-Lys-Leu-Lys-Ser-Ile-Val-Ser-Trp-Ala-Lys-Lys-Val-Leu-NH2, showing amphililic property.
Mastoparan Btook an unordered conformation in aqueous solution while the peptide changed its conformation from unordered to ordered helical conformation in triflouroethanol (TEF) solution (20%-60% TFE). And the helical conformation exsited stablely under proper TFE/H2O environment. So it is possible to determine the solutional structure of MPB on this environment by using two-dimensional 1HNMR techniques and computer modelling techniques. I present here an NMR study of the structure of MPB in 40%TFE/60%H2O solution.
From the two-dimensional nuclear Overhauser enhancement spectra, a set of distance restrainsis derived and used as the basis for threedimensional structure determination by distance geometry, restrained molecular dynamic and hybrid distance-simulated annealing algorithim. All the NMR structures determined by above three algorithim are located on the same conformation space. The resulting structures exhibited a reasonably well defined a-helical conformation with larger fluctuations occured only at the two N-terminal residues. And the side chains are less defined than backbone atoms. The structural feathers of the converged MPB structures exhibited a cathionic amphiphilic helical conformation (residue3-14) with the hydrophilic residues, such as Lys4, Lys11, Lys12, and Ser8, are located in one side (hydrophlic face) of molecule, while the hydrophobic residues, such as Leu3, Ile6, Trp9, Ala10, Val13 and Leu14, are located in another side (hydrophobic face) of molecule. Ser5 is located in the intersection of hydrophilic and hydrophobc face, and hydrophobic residue Val7 in the hydrophilic side.