PSGL-1的構形探討：圓二色偏極光譜及核磁共振光譜研究

Conformational Investigation of PSGL-1: CD and NMR Spectroscopic Studies

葉威廷(Wei-Ting Yeh)

指導教授 ： 林英智

國立臺灣大學/理學院/化學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.10510

摘要

一系列經過修飾的PSGL-1醣肽樣品，被採用來探討醣化以及硫酸化對於整個分子構形的影響。樣品被溶解於不同的媒介中，以研究他們圓二色偏極光譜訊號的穩定度；利用光譜模擬程式k2d，以數值的方式來分析樣品曲線的不同成份組成；並施以全波長的掃瞄，來證實芳香性發色團對整個光譜的貢獻。比較了未硫酸化及硫酸化的樣品組合，不同糖化程度的樣品也被拿來比較。並且實行核磁共振實驗，希望能得到關於真實分子的空間分布資訊。藉由各種不同的一維及二維光譜實驗，得到互補的數據，才能完成未硫酸化及硫酸化的光譜全分析。原子核經由空間的相關性也才能因而確認，並轉化成模擬計算中有用的限制條件。不論採用間奧氏效應為條件限制與否，都經由最佳化的幾何構形為起點，利用蒙地卡羅演算法來找尋穩定的分子構形。

關鍵字

醣肽分子構形 ； 圓二色偏極光譜 ； 核磁共振 ； 分子模擬

並列摘要

The PSGL-1 samples, a series of modified octapeptides, were taken to investigate the influence of glycosylation and sulfation on the conformation of whole molecule. Samples were dissolved in three different media to examine the stability of CD signals. CD fitting program k2d was used to numerically analyze the compositions of each CD curve. Full-length scan was performed to understand the contribution of aromatic chromophore. The unsulfated-and-sulfated combinations were compared as well as samples of different glycosylation extent. NMR experiments were applied to obtain information of real spatial arrangements. With the assistances of various one- and two-dimensional NMR experiments, evidences were obtained to accomplish the full assignments for sulfated and unsulfated samples. Nuclear correlations through space were thus recognized and transformed into useful constraints for calculations. Optimized starting geometry was used to search stable molecular conformations by using Monte Carlo algorithm in consistence with and without NOE constraints.

並列關鍵字

glycopeptide ； conformation ； CD ； NMR ； molecular modeling

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