...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Applied Microbiology >Characterization of a Nitrilase and a Nitrile Hydratase from Pseudomonas sp. Strain UW4 That Converts Indole-3-Acetonitrile to Indole-3-Acetic Acid
【24h】

Characterization of a Nitrilase and a Nitrile Hydratase from Pseudomonas sp. Strain UW4 That Converts Indole-3-Acetonitrile to Indole-3-Acetic Acid

机译：假单胞菌属的一种腈水解酶和一种腈水合酶的表征。 UW4菌株将吲哚-3-乙腈转化为吲哚-3-乙酸

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Indole-3-acetic acid (IAA) is a fundamental phytohormone with the ability to control many aspects of plant growth and development. Pseudomonas sp. strain UW4 is a rhizospheric plant growth-promoting bacterium that produces and secretes IAA. While several putative IAA biosynthetic genes have been reported in this bacterium, the pathways leading to the production of IAA in strain UW4 are unclear. Here, the presence of the indole-3-acetamide (IAM) and indole-3-acetaldoxime/indole-3-acetonitrile (IAOx/IAN) pathways of IAA biosynthesis is described, and the specific role of two of the enzymes (nitrilase and nitrile hydratase) that mediate these pathways is assessed. The genes encoding these two enzymes were expressed in Escherichia coli , and the enzymes were isolated and characterized. Substrate-feeding assays indicate that the nitrilase produces both IAM and IAA from the IAN substrate, while the nitrile hydratase only produces IAM. The two nitrile-hydrolyzing enzymes have very different temperature and pH optimums. Nitrilase prefers a temperature of 50°C and a pH of 6, while nitrile hydratase prefers 4°C and a pH of 7.5. Based on multiple sequence alignments and motif analyses, physicochemical properties and enzyme assays, it is concluded that the UW4 nitrilase has an aromatic substrate specificity. The nitrile hydratase is identified as an iron-type metalloenzyme that does not require the help of a P47K activator protein to be active. These data are interpreted in terms of a preliminary model for the biosynthesis of IAA in this bacterium.
机译：吲哚-3-乙酸（IAA）是一种基本的植物激素，具有控制植物生长发育的许多方面的能力。假单胞菌UW4菌株是一种根际植物生长细菌，可产生并分泌IAA。尽管在该细菌中已报道了几种推定的IAA生物合成基因，但导致UW4菌株产生IAA的途径尚不清楚。在此，说明了IAA生物合成的吲哚-3-乙酰胺（IAM）和吲哚-3-乙醛肟/吲哚-3-乙腈（IAOx / IAN）途径的存在，以及两种酶（硝化酶和介导这些途径的腈水合酶）。编码这两种酶的基因在大肠杆菌中表达，并分离和鉴定了这些酶。底物进料测定表明腈水解酶可从IAN底物产生IAM和IAA，而腈水合酶仅产生IAM。两种腈水解酶的最佳温度和pH值相差很大。腈水解酶优选温度为50℃且pH为6，而腈水合酶优选温度为4℃且pH为7.5。基于多个序列比对和基序分析，理化性质和酶分析，得出结论，UW4腈水解酶具有芳香族底物特异性。腈水合酶被鉴定为不需要P47K激活蛋白来激活的铁型金属酶。这些数据是根据该细菌中IAA生物合成的初步模型来解释的。

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