再生丝素水溶液在存放过程中的结构变化

通过拉曼光谱法研究了不同浓度的再生丝素水溶液在常温下存放不同时间的构象变化。发现再生丝素水溶液在静置存放过程中会有结构的变化即无规巷曲和α螺旋向β折叠结构的转变，并且浓度越大，构象转变越快。当溶液处于流动状态时，其构象转变速度要快于静置状态下的转变。同时发现对于新鲜制备出的再生丝素水溶液随浓度的增加，也会发生构象的转变。     

两种杯[4]芳烃母体化合物的简易合成方法及其性质研究

通过对叔丁基苯酚的聚合反应,再脱去叔丁基,依次得到两种有用的杯【4】芳烃,它们是大多数杯芳烃衍生物的合成子。本文参考现有文献,将合成路线加以改进和优化,较高产率地得到这两种杯【4】芳烃。依次测定了它们的物理性质、元素分析及红外光谱数据,并通过波谱数据表征了它们各自的构象,证实其确为目标产物,从而验证了此合成路线的可行性和可靠性。     

The synthesis of a new type of calix[4]arene with chiral pendant

Two new chiral calixarenes were synthesized by condensing 1,3-bis-chlorocarbomethyl-calix[4] arenes with (1S, 2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol, a by-product from antibiotic industry, and were characterized by¹H-NMR, MS-FAB, and elemental analysis. The¹H-NMR spectra show that those molecules assume a cone conformation in solution. Foundation item: Supported by the Zi-Qiang Science Foundation of Wuhan University Biography: He Yong-bing, (1945-), male, Professor, research direction: supramolecular chemistry.     

Molecular Properties在海藻糖分子构象分析中的应用

应用Molecular Properties(MP)软件中内置的分子动力学计算功能,对海藻糖分子构象进行了研究,所得到的可能的最优构象的结构参数与文献报道数值基本吻合,表明了利用MP软件研究分子构象的可行性.按照XML 1.0标准编写了海藻糖分子可能的最优构象的CML格式分子结构文件,以便于网上交流和检索.     

几个包含胱氨酸类环肽的合成及结构研究

以胱氨酸二甲酯、酒石酸二酰氯、对苯二甲酰氯、草酰氯为起始物,在高度稀释的条件下进行反应,合成了24,28,30元环的3个类环肽,收率分别为40%,12%,30%.FAB-MS结果证实,在反应条件下分别得到了2 2和3 3产物.1HNMR研究证实,这些类环肽在DMSO-d6中分别具有C2或C3对称构象;而胱氨酸二甲酯与对苯二甲酰氯缩合得到的产物在CDCl3中是多种构象的混合物.     

Structure of Cyclopeptide C10 in Solution

Ｍｕｔｅｒ［１］ａｖｏｉｄｅｄｔｈｅｐｒｏｔｅｉｎｆｏｌｄｉｎｇｐｒｏｂｌｅｍｂｙｄｅｖｅｌｏｐｉｎｇａｍｅｔｈｏｄｃａｌｅｄｔｅｍｐｌａｔｅｄ－ａｓｓｅｍｂｌｉｎｇｓｙｎｔｈｅｔｉｃｐｒｏｔｅｉｎ（ＴＡＳＰ）ｗｈｉｃｈｉｎｔｒｏｄｕｃｅｄａｔｅｍｐ...     

溶菌酶水溶液的激光拉曼谱

本文报道了溶菌酶水溶液的激光拉曼谱。酰胺Ⅰ振动谱带在1657cm~(-1),酰胺Ⅱ振动谱带在1302和1253cm~(-1),酪氨酸残基的特征谱带在854和837cm~(-1)。硫—硫桥键的振动谱带在505cm~(-1)。并由此定性地证明了该蛋白质分子的肽链主要由α—螺旋和无规则卷曲组成,酪氨酸残基在分子中呈三分之二“暴露”式,硫—硫键部位的几何构型为扭式—扭式—扭式。     

Photo-oxidation of histidine as a probe for aminoterminal conformational changes during fibrinogen-fibrin conversion

Fibrinogen is known to become unclottable when irradiated with light in the presence of methylene blue, the loss of clottability being due to photo-oxidation of the histidine at position 16 of the B<beta> chain. In the present investigation it could be demonstrated that not only this histidine but also the one at position 24 of the A<alpha> chain was modified and that the rates of modification could be modulated by fibrinopeptide release, polymerization inhibition and denaturation. Accordingly, the histidine modifications can be used as probes for surface accessibility of and conformational differences among the various forms of the protein. Both histidines are shielded by the fibrin polymer structure. Fibrinopeptide A release alone leads to maximal protection of the one in the A<alpha> chain, but only partial protection of the one in the B<beta> chain. Subsequent fibrinopeptide B release leads to maximal protection of the one in the B<beta> chain. The differential effects indicate that two conformational changes have occurred. Polymerization inhibition reverses the protective effect. Denaturation leads to maximal and equal modification in all samples as a consequence of the loss of native conformation. Received 8 October 1996; accepted 15 October 1996     

(+)-(β-去氢枞酰氧基)乙基三甲基溴化铵的核磁共振谱解析

( )—(β—去氢枞酰氧基)乙基三甲基溴化铵的^1H—NMR和H—HCOSY，分子的A环以椅式存在，而B环则以稳定的扭船式存在，从而解析了它的构象。