利用CD和NMR研究合成的神經胜肽片段hNPY【21-31】之結構

人類神經胜肽Y(Human Neuropeptide Y, hNPY)在水溶液中具有α-螺旋結構，且低濃度下結構為單體，高濃度時則為雙體。其結構有特定作用機制:單體下先與膜微脂粒(membrane micelle)結合後進一步與GPCRs(G protein-coupled receptors)作用。固相胜肽合成法(Solid Phase Peptide Synthesis)合成hNPY片段序列(hNPY[21-31])，經由高效能液相層析儀純化，質譜儀確認分子量，再用圓二色光譜(Circular Dichroism)觀察不同比例TFE溶液下，二級結構的變化，選擇100%水溶液與50%TFE兩溶液做結構測量與討論。用二維核磁共振(two-dimensional NMR)的光譜: COSY、TOCSY、ROESY、NOESY、[1H, 13C]-HSQC及光譜判定(Assignment)和光譜循序判定(Sequential assignment)，各別判定兩溶液之11個殘基質子與13碳的化學位移。經由NOE限制條件分別計算兩溶液之3D結構，100%水溶液呈現鬆散不規則結構，50%TFE溶液則在24Leu~28Asn出現α-螺旋結構。配合CD、CSI(Chemical Shift Index)、NMR、結構計算，討論兩比例溶液之結構差異，並與NPY結構比較。

關鍵字

二維核磁共振；圓二色光譜儀；神經胜肽；固相胜肽合成法

並列摘要

Human Neuropeptide Y(hNPY) has a well-defined α-helical structure in solution, and is monomer at low concentration, dimer at high concentration. It has specific binding mechanism: First, the monomer structure binds with membrane micelle, and further interacts with G protein-coulpled receptors(GPCRs). We synthesize neuropeptide fragment hNPY[21-31] by solid phase peptide synthesis, purified by RP-HPLC and made sure the molecular weight by Mass. The conformation and dynamics of hNPY[21-31] in difference solvent condition is studied by CD and 2D NMR experiment. 2D NMR experiments of COSY, TOCSY, ROESY, NOESY, and [1H, 13C]-HSQC were acquired. With NOE restrained structural calculation, the major structure of hNPY[21-31] in 100% H2O is random coil and form regular α-helical structure between 24Leu and 28Asn in 50%TFE/50% H2O. Combination of CD, NMR, and XPLOR molecular calculation, we can investigate the conformational difference between 100%H2O and 50%TFE /50%H2O, and compare with native NPY.

並列關鍵字

2D NMR ； CD ； NPY ； PP ； SPPS

參考文獻

21. 余靖,李長欣核磁共振專輯(二), 1998, 國科會精密儀器發展中心。

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利用CD和NMR研究合成的神經胜肽片段hNPY【21-31】之結構

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