...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Three-Dimensional Structure of RTD-1, a Cyclic Antimicrobial Defensin from Rhesus Macaque Leukocytes
【24h】

Three-Dimensional Structure of RTD-1, a Cyclic Antimicrobial Defensin from Rhesus Macaque Leukocytes

机译：恒河猴猕猴白细胞循环抗菌防御素RTD-1的三维结构

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

Most mammalian defensins are cationic peptides of 29—42 amino acids long, stabilized by three disulfide bonds. However, recently Tang et al. (1999, Science 286, 498—502) reported the isolation of a new defensin type found in the leukocytes of rhesus macaques. In contrast to all the other defensins found so far, rhesus theta defensin-1 (RTD-1) is composed of just 18 amino acids with the backbone cyclized through peptide bonds. Antibacterial activities of both the native cyclic peptide and a linear form were examined, showing that the cyclic form was 3-fold more active than the open chain analogue [Tang et al. (1999) Science 286, 498—502]. To elucidate the three-dimensional structure of RTD-1 and its open chain analogue, both peptides were synthesized using solid-phase peptide synthesis and tert-butyloxycarbonyl chemistry. The structures of both peptides in aqueous solution were determined from two-dimensional 1H NMR data recorded at 500 and 750 MHz. Structural constraints consisting of interproton distances and dihedral angles were used as input for simulated-annealing calculations and water refinement with the program CNS. RTD-1 and its open chain analogue oRTD-1 adopt very similar structures in water. Both comprise an extended /3-hairpin structure with turns at one or both ends. The turns are well defined within themselves and seem to be flexible with respect to the extended regions of the molecules. Although the two strands of the /3-sheet are connected by three disulfide bonds, this region displays a degree of flexibility. The structural similarity of RTD- 1 and its open chain analogue oRTD-1, as well as their comparable degree of flexibility, support the theory that the additional charges at the termini of the open chain analogue rather than overall differences in structure or flexibility are the cause for oRTD- l’s lower antimicrobial activity. In contrast to numerous other antimicrobial peptides, RTD- 1 does not display any amphiphilic character, even though surface models of RTD- 1 exhibit a certain clustering of positive charges. Some amide protons of RTD-1 that should be solvent-exposed in monomeric /3-sheet structures show low-temperature coefficients, suggesting the possible presence of weak intermolecular hydrogen bonds.
机译：大多数哺乳动物防御素是长29-42个氨基酸的阳离子肽，由三个二硫键稳定。然而，最近唐等人。 （1999，Science 286，498-502）报道了在猕猴的白细胞中发现的一种新的防御素类型的分离。与迄今为止发现的所有其他防御素相比，恒河猴防御素-1（RTD-1）仅由18个氨基酸组成，其主链通过肽键环化。检查了天然环状肽和线性形式的抗菌活性，表明环状形式的活性是开放链类似物的3倍[Tang等。 （1999）Science 286，498-502]。为了阐明RTD-1及其开放链类似物的三维结构，使用固相肽合成和叔丁氧羰基化学方法合成了这两种肽。根据在500和750 MHz处记录的二维1H NMR数据确定水溶液中两种肽的结构。由质子间距和二面角组成的结构约束被用作CNS程序进行模拟退火计算和水质净化的输入。 RTD-1及其开放链类似物oRTD-1在水中采用非常相似的结构。两者都包括延伸的/ 3-发夹结构，其一端或两端具有匝。匝在其内部被很好地定义，并且相对于分子的延伸区域似乎是灵活的。尽管/ 3-sheet的两条链通过三个二硫键连接，但该区域显示一定程度的柔韧性。 RTD-1及其开放链类似物oRTD-1的结构相似性以及相当的灵活性，支持以下理论：开放链类似物末端的额外电荷而不是结构或灵活性的总体差异是导致oRTD-1的抗菌活性降低。与许多其他抗菌肽相反，RTD-1不显示任何两亲特性，即使RTD-1的表面模型显示出一定的正电荷簇。 RTD-1的某些酰胺质子应以溶剂暴露在单体/ 3-片结构中，显示出较低的温度系数，表明可能存在弱的分子间氢键。

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