...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Acta Crystallographica, Section B. Structural Science >Structures of Quinoxaline Antibiotics
【24h】

Structures of Quinoxaline Antibiotics

机译：喹喔啉抗生素的结构

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The crystal structures of three quinoxaline antibiotics -echinomycin 2QN, triostin C and the C222j form of triostin A - have been determined, and the structure of the P2i2i2i form of triostin A has been re-refined against our previously reported data. The molecular conformations are compared with those deduced from NMR data and those reported for two complexes of triostin A with oligonucleotides. Although the depsipeptide ring conformations are basically similar, the effective twofold molecular symmetry is violated by the folding of one of the quinoxaline chromophores in echinomycin 2QN and by a rotation of one of the ester planes with the formation of an intramolecular hydrogen bond in triostin C. In the oligonucleotide complexes of triostin A the chirality of the disulfide bridge is inverted. The alanine NH groups are involved in intermolecular hydrogen bonds in all four structures, and (except in echinomycin 2QN) the stacking of the chromophores in the crystal emulates the intercalation involved in DNA complex formation. In echinomycin 2QN, the antibiotic molecules are hydrogen bonded to form a helix along the crystallographic 65 screw axes, with a channel of disordered solvent running through the middle of the helix. Crystal data: (1), echinomycin 2QN, C53H66NioO,2S2.2.5(C3H60).2.5(H20), Mr = 1289.5, hexagonal, P65, a = 6 = 22.196 (15), c = 24.64 (2) A, V = 10513(13)A3, Z = 6, Dx = 1.222Mgm-3, A(CuA:a) = 1.5418 A, n = 1.275 mm~(-1), T= 193 K,R = 9.0% for 4828 I>2cr(7) and 11.8% for all 7102 unique reflections; (2), triostin C, C_(54)H_(70)N_(120)i_2S_2. 0.67(CHCl_3). 0.67(H_(20)), Mr = 1234.2, orthorhombic, P_2A_2U a = 16.054(8), 6 = 17.128(9), c = 22.706 (12) A, V- 6244 (6) A3,Z = 4, Z= 1.313 Mgnr3, 0.239mm~(-1), N=188K, I and 14.0% for all (3), triostin A, Mr = 1347.6, orthorhombic, P2i2i2,, a = 20.94(2), fo= 18.53(2), c= 18.80 (2) A, V= 7292 (13) A3, Z = 4, Dx = 1.228 MgnT3, = 1.5418 A, M= 1.245 mm~(-1), T=293K, R =6.8% for 2116 I>2a(I) and 9.3% for all 2928 unique reflections; (4), triostin A, C_(50)H_(62)N_(120)12S_2.HCL_2(C_3H_7NO), Mr = 1269.9, monoclinic, C222,, a= 10.622(10), b = 17.035(17), c = 35.21 (3) A, V = 6371 (10) A3, Z=4, Dx = 1.324 Mgnr3, X(UoKa) = 0.71073 A, /M = 0.199 mm~(-1), T=153K, R = 7.5% for 2164 I>2
机译：已经确定了三种喹喔啉抗生素的晶体结构-棘霉素2QN，曲古汀C和曲古汀A的C222j形式-并已根据我们先前报道的数据重新精制了曲古汀A的P2i2i2i形式的结构。将分子构象与从NMR数据推导的分子构象以及报道的三链蛋白A与寡核苷酸的两种复合物的分子构象进行比较。尽管二肽环的构象基本相似，但由于埃奇霉素2QN中一个喹喔啉生色团的折叠以及酯平面之一的旋转并在triostin C中形成了一个分子内氢键，从而破坏了有效的双重分子对称性。在肌钙蛋白A的寡核苷酸复合物中，二硫键的手性反转。丙氨酸的NH基团参与所有四个结构的分子间氢键，并且（除棘霉素2QN中的）发色团在晶体中的堆积模拟了DNA复合物形成所涉及的嵌入。在棘轮霉素2QN中，抗生素分子氢键结合，沿着晶体学的65个螺旋轴形成一个螺旋，其中无序溶剂通道穿过螺旋的中间。晶体数据：（1），棘霉素2QN，C53H66NioO，2S2.2.5（C3H60）.2.5（H20），Mr = 1289.5，六角形，P65，a = 6 = 22.196（15），c = 24.64（2）A，V = 10513（13）A3，Z = 6，Dx = 1.222Mgm-3，A（CuA：a）= 1.5418 A，n = 1.275 mm〜（-1），T = 193 K，R = 9.0％（对于4828 I）对于所有7102个唯一反射，> 2cr（7）和11.8％; （2），肌钙蛋白C，C_（54）H_（70）N_（120）i_2S_2。 0.67（CHCl_3）。 0.67（H_（20）），Mr = 1234.2，正交，P_2A_2U a = 16.054（8），6 = 17.128（9），c = 22.706（12）A，V-6244（6）A3，Z = 4，Z = 1.313 Mgnr3，0.239mm〜（-1），N = 188K，全部（3）的I和14.0％，triostin A，Mr = 1347.6，斜方体，P2i2i2，a = 20.94（2），fo = 18.53（2 ），c = 18.80（2）A，V = 7292（13）A3，Z = 4，Dx = 1.228 MgnT3，= 1.5418 A，M = 1.245 mm〜（-1），T = 293K，R = 6.8％ 2116 I> 2a（I）和2928个唯一反射的9.3％; （4），Triostin A，C_（50）H_（62）N_（120）12S_2.HCL_2（C_3H_7NO），Mr = 1269.9，单斜，C222，a = 10.622（10），b = 17.035（17），c = 35.21（3）A，V = 6371（10）A3，Z = 4，Dx = 1.324 Mgnr3，X（UoKa）= 0.71073 A，/ M = 0.199 mm〜（-1），T = 153K，R = 7.5 2164 I> 2

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号