• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Molecular Biology >Crystal structure of a novel mid-gut procarboxypeptidase from the cotton pest Helicoverpa armigera
【24h】

Crystal structure of a novel mid-gut procarboxypeptidase from the cotton pest Helicoverpa armigera

机译：棉铃虫Helicoverpa armigera的新型中肠原羧肽酶的晶体结构

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 cotton bollworm Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) is one of the most serious insect pests in Australia, India and China. The larva causes substantial economical losses to legume, fibre, cereal oilseed and vegetable crops. This pest has proven to be difficult to control by conventional means, mainly due to the development of pesticide resistance. We present here the 2.5 Angstrom crystal structure from the novel procarboxypeptidase (PCPAHa) found in the gut extracts from H. armigera larvae, the first one reported for an insect. This metalloprotease is synthesized as a zymogen of 46.6 kDa which, upon in vitro activation with Lys-C endoproteinase, yields a pro-segment of 91 residues and an active carboxypeptidase moiety of 318 residues. Both regions show a three-dimensional structure quite similar to the corresponding structures in mammalian digestive carboxypeptidases, the most relevant structural differences being located in the loops between conserved secondary structure elements, including the primary activation site. This activation site contains the motif (Ala)(5)Lys at the C terminus of the helix connecting the pro- and the carboxypeptidase domains. A remarkable feature of PCPAHa is the occurrence of the same (Ala)(6)Lys near the C terminus of the active enzyme. The presence of Ser255 in PCPAHa instead of Ile and Asp found in the pancreatic A and B forms, respectively, enlarges the S1' specificity pocket and influences the substrate preferences of the enzyme. The C-terminal tail of the leech carboxypeptidase inhibitor has been modelled into the PCPAHa active site to explore the substrate preferences and fine enzymatic mechanism of this enzyme.
机译：棉铃虫Helicoverpa armigera（Hubner）（鳞翅目：夜蛾科）是澳大利亚，印度和中国最严重的害虫之一。幼虫对豆类，纤维，谷类油料种子和蔬菜作物造成重大的经济损失。事实证明，这种有害生物难以通过常规手段加以控制，这主要归因于对农药的抗性发展。我们在这里介绍了从棉铃虫幼虫肠道提取物中发现的新型羧肽酶（PCPAHa）的2.5埃晶体结构，这是第一种报道为昆虫的。该金属蛋白酶被合成为46.6kDa的酶原，其在体外用Lys-C内蛋白酶活化后产生91个残基的前节和318个残基的活性羧肽酶部分。这两个区域均显示出非常类似于哺乳动物消化羧肽酶中相应结构的三维结构，最相关的结构差异位于保守的二级结构元件之间的环中，包括一级激活位点。该活化位点在连接前肽和羧肽酶结构域的螺旋的C末端包含基序（Ala）（5）Lys。 PCPAHa的显着特征是在活性酶C末端附近出现了相同的（Ala）（6）Lys。在PCPAHa中而不是分别以胰腺A和B形式发现的Ile和Asp的Ser255的存在会扩大S1'的特异性口袋并影响酶的底物偏好。水ech羧肽酶抑制剂的C末端尾巴已被建模为PCPAHa活性位点，以探索该酶的底物偏好和精细的酶促机制。

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