The conformational study of a peptidepheromone-sodefrin

• Main Authors: Chien-Pin Hsu, 徐建斌
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/tvfnbr

碩士 === 朝陽科技大學 === 應用化學系碩士班 === 91 === The conformation of the first found amphibian peptide pheromone- sodefrin, NH2-Ser-Ile-Pro-Ser-Lys-Asp-Ala-Leu-Leu-Lys-OH is investigated by CD and NMR spectroscopy. It is found that, in aqueous solution, sodefrin exists mainly as a random coil. The introduction of TFE into the solution resulted in an increase of the helix content. A primary structure derived from NMR experiments and distance geometry revealed the existence of a nascent helix in C-terminal of the peptide in 50% TFE solution. This result is consistent with the chemical shift characteristic value and temperature coefficient of backbone amide proton for each residue. Substitution of proline for alanine at position 3 in the sequence of sodefrin caused a reduction in the helix content. The deviation of the mutant structure from that of wild sodefrin is monitored by circular dichroism experiments and further identified by a three dimensional curve, which was composed of the information from both variable temperature and TFE titration experiments. Based on these observations proline, at N-terminal of sodefrin, seems to be able to stabilize the helical structure in C-terminal of the short peptide.