...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >A functional Ni-Ni-[4Fe-4S] cluster in the monomeric acetyl-CoA synthase from Carboxydothermus hydrogenoformans
【24h】

A functional Ni-Ni-[4Fe-4S] cluster in the monomeric acetyl-CoA synthase from Carboxydothermus hydrogenoformans

机译：产自羧甲基甲烷的单体乙酰辅酶A合酶中的功能性Ni-Ni- [4Fe-4S]簇

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

In anaerobic microorganisms employing the acetyl-CoA pathway, acetyl-CoA synthase (ACS) and CO dehydrogenase (CODH) form a complex (ACS/CODH) that catalyzes the synthesis of acetyl-CoA from CO, a methyl group, and CoA. Previously, a [4Fe-4S] cubane bridged to a copper-nickel binuclear site (active site cluster A of the ACS component) was identified in the ACS_(Mt)/CODH_(Mt) from Moorella thermoacetica whereas another study revealed a nickel-nickel site in the open form of ACS_(Mt), and a zink-nickel site in the closed form. The ACS_(Ch) of the hydrogenogenic bacterium Carboxydothermus hydrogenoformans was found to exist as an 82.2-kDa monomer as well as in a 1:1 molar complex with the 73.3-kDa CODHIII_(Ch). Homogenous ACS_(Ch) and ACS_(Ch)/CODHIII_(Ch) catalyzed the exchange between [1-~(14)C]acetyl-CoA and ~(12)CO with specific activities of 2.4 or 5.9 μmol of CO per min per mg, respectively, at 70℃ and pH 6.0. They also catalyzed the synthesis of acetyl-CoA from CO, methylcobalamin, corrinoid iron-sulfur protein, and CoA with specific activities of 0.14 or 0.91 μmol of acetyl-CoA formed per min per mg, respectively, at 70℃ and pH 7.3. The functional cluster A of ACS_(Ch) contains a Ni-Ni-[4Fe-4S] site, in which the positions proximal and distal to the cubane are occupied by Ni ions. This result is apparent from a positive correlation of the Ni contents and negative correlations of the Cu or Zn contents with the acetyl-CoA/CO exchange activities of different preparations of monomeric ACS_(Ch), a 2.2-A crystal structure of the dithionite-reduced monomer in an open conformation, and x-ray absorption spectroscopy.
机译：在采用乙酰辅酶A途径的厌氧微生物中，乙酰辅酶A合酶（ACS）和一氧化碳脱氢酶（CODH）形成复合物（ACS / CODH），该复合物催化由一氧化碳，甲基和辅酶A合成乙酰辅酶A.先前，在Moorella thermoacetica的ACS_（Mt）/ CODH_（Mt）中鉴定了桥接至铜-镍双核位点（ACS组分的活性位点簇A）的[4Fe-4S]古巴，而另一项研究表明，镍- ACS_（Mt）的开放形式的镍站点和封闭形式的zink-镍站点。发现氢生细菌产氢羧化甲烷的ACS_（Ch）以82.2-kDa单体的形式以及与73.3-kDa CODHIII_（Ch）的1：1摩尔配合物形式存在。均质ACS_（Ch）和ACS_（Ch）/ CODHIII_（Ch）催化[1-〜（14）C]乙酰辅酶A和〜（12）CO之间的交换，比活度为每分钟每分钟2.4或5.9μmolCO分别在70℃和pH 6.0下。他们还催化了在70℃和pH值为7.3下，CO，甲基钴胺素，类rinrinoid铁硫蛋白和CoA的比活性分别为每分钟每毫克形成0.14或0.91μmol乙酰-CoA的合成。 ACS_（Ch）的功能簇A包含一个Ni-Ni- [4Fe-4S]位点，在该位点附近和靠近古巴的位置被Ni离子占据。从不同的单体ACS_（Ch）制剂，连二亚硫酸盐晶体的2.2-A晶体结构的制备中，镍含量的正相关和铜或锌含量的负相关与乙酰-CoA / CO交换活性的负相关可以明显看出这一结果。还原成开放构象的单体，以及X射线吸收光谱。

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