• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Structural insights into the active site of alpha-carbonic anhydrases.
【24h】

Structural insights into the active site of alpha-carbonic anhydrases.

机译：对α-碳酸酐酶活性位点的结构见解。

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

Carbonic anhydrases (CA) are ubiquitously expressed metalloenzymes that are found in all organisms, ranging from bacteria to humans. Human CA II (HCA II) is the most well-studied and utilizes a zinc-hydroxide mechanism to catalyze the reversible hydration of carbon dioxide to produce bicarbonate and a proton. Catalysis involves an intramolecular proton transfer event that delivers an excess proton from the zinc-bound water to an internal proton acceptor, His64. His64 then shuttles this proton to the bulk solvent, thus regenerating the active site for the next round of catalysis.;An extensive analysis of the structural and kinetic stability of wild type and several mutants of HCA II was conducted over a broad pH range. The results show that the enzyme, and the water network in the active site, is extremely stable. It is also the first observation of sulfate ion binding in the active site of wild type HCA II. Attempts to disrupt not only the proton shuttle His64, but other residues involved in stabilizing the water network were also successful as reflected in changes of the measured proton transfer rates. Overall, the results give insights into the structural requirements for efficient proton transfer as catalyzed by CA. To directly observe the active site waters and protonation state of His64, perdeuterated wild type HCA II was produced, crystallized and the X-ray structure determined. This work lays the foundation for future proposed neutron diffraction experiments.;Classical, clinically used CA inhibitors (CAI) are not very water-soluble and this feature has implications for bioavailability of these drugs. The X-ray structures of two novel, water-soluble CAIs bound to HCA II were determined. They reveal that incorporation of spacer groups and fluorines can change the binding modes of CAIs. This work has implications for the clinical use and bioavailability of systemically applied CAIs and for targeting different isozymes of HCA.;A CA from mosquito larvae (AaCA1) was also expressed, purified, and structurally and kinetically characterized. AaCA1 is a high activity CA that shows inhibition with all the classical sulfonamide-based CAIs. This enzyme represents an interesting new drug target for the control of mosquito populations and further understanding of CA function in other organisms.
机译：碳酸酐酶（CA）是在从细菌到人类的所有生物体中普遍存在的表达的金属酶。人们对CA II（HCA II）的研究最为深入，它利用氢氧化锌机理催化二氧化碳的可逆水合作用，从而产生碳酸氢盐和质子。催化涉及分子内质子转移事件，该事件将过量的质子从与锌结合的水中传递到内部质子受体His64。然后His64将这个质子穿梭到大量溶剂中，从而再生了活性位点，用于下一轮催化。在宽的pH范围内，对野生型和几种HCA II突变体的结构和动力学稳定性进行了广泛的分析。结果表明，酶和活性位点中的水网络非常稳定。这也是在野生型HCA II活性位点结合硫酸根离子的首次观察。不仅尝试破坏质子穿梭His64，而且还成功破坏了稳定水网络的其他残留物，这在测得的质子传递速率的变化中得到了反映。总体而言，结果提供了对CA催化的高效质子转移的结构要求的见解。为了直接观察His64的活性位点水和质子化状态，产生了氘化的野生型HCA II，使其结晶并确定了X射线结构。这项工作为将来提出的中子衍射实验奠定了基础。；经典的，临床上使用的CA抑制剂（CAI）水溶性不高，这一特征对这些药物的生物利用度有影响。确定了与HCA II结合的两种新型水溶性CAI的X射线结构。他们揭示了结合间隔基和氟可以改变CAI的结合方式。这项工作对全身应用的CAI的临床用途和生物利用度以及靶向HCA的不同同工酶都有影响。还对蚊幼虫（AaCA1）的CA进行了表达，纯化，结构和动力学表征。 AaCA1是一种高活性CA，对所有经典的基于磺酰胺的CAI均显示出抑制作用。该酶代表了一种有趣的新药物靶标，可用于控制蚊子种群并进一步了解其他生物中的CA功能。

著录项

  • 作者

    Fisher, Suzanne Zoe.;

  • 作者单位

    University of Florida.;

  • 授予单位 University of Florida.;
  • 学科 Biology General.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 164 p.
  • 总页数 164
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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