二水合氯精氨酸的构象变化  

Conformational changes of arginine dichloride dihydrate

作　　者：鲜亮[1] 吕功煊[1] 

机构地区：[1]中国科学院兰州化学物理研究所羰基合成与选择氧化国家重点实验室

出　　处：《化学研究与应用》2007年第5期474-478,共5页Chemical Research and Application

基　　金：国家自然科学基金的资金资助(90210027)

摘　　要：以X光衍射实验对二水合氯酸的晶体结构进行了研究,重点讨论了影响精氨酸构象变化的主要因素并比较了在不同阴离子存在条件下精氨酸构象的变化情况。该晶体为单斜晶系,P21/c,a=11.0490(18);b=8.4876(13);c=11.2261(17);β=91.386(2);°Z=4;Dx=1.443Mg.m-3。精氨酸分子以顺式和反式两种构象沿C轴方向交错排列而羧基氧原子和相邻分子中的α-氨基N-H以氢键相连,形成常见的“头尾”相连构型;分子中的结晶水参与氢键的形成,类似“盐桥”作用;氯离子参与电荷平衡并和精氨酸的N-H形成较强的氢键作用和静电吸引力。上述作用使得精氨酸分子晶体形成了三维氢键网状超分子结构。Single crystal of Arginine dichloride dihydrate was studide by x-ray diffraction expriments in emphasis of main influence factors of arginine conformational variation, and was also compared with its other conformations in the existence of different anions. The single crystal is Monoelinic,P21/c,a = 11. 0490（18） A; b = 8. 4876（13） A; c = 11. 2261 （ 17）A;β =91. 386（2） °; Z =4; D, = 1. 443 Mg · m^3. Arginine molecules interlaced with each other in cis-and tram-conformations to arrange along c axis, and the oxygen atoms on carboxyl group and the N-H on α - amino group connected with each other by hydrogen bonds to form a common ＂head-tail＂ connecting conformation. Crystal water molecules formed hydrogen bonds with arginine and acted as a ＂salt bridge＂, and chloride ions were also involved in the formation of hydrogen bonds and static interactions with N-H on arginine and took part in the charge balance with arginine. All the above interactions make arginine form hydrogen bonding superamolecular network structure in three-dimension.

关 键 词：精氨酸 构象 氢键 

分 类 号：O742.6[理学—晶体学]