Structural basis for a homodimeric ATPase subunit of an ECF transporter

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• 作者：Chengliang Chai (1) (3)
  You Yu (2)
  Wei Zhuo (2)
  Haifeng Zhao (2)
  Xiaolu Li (2)
  Na Wang (2)
  Jijie Chai (1) (2)
  Maojun Yang (2)
  
• 关键词：CbiO ; Cobalt ; ECF ; ATPase ; Thermoanaerobacter tengcongensis
• 刊名：Protein & Cell
• 出版年：2013
• 出版时间：October 2013
• 年：2013
• 卷：4
• 期：10
• 页码：793-801
• 全文大小：
• 作者单位：Chengliang Chai (1) (3)
  You Yu (2)
  Wei Zhuo (2)
  Haifeng Zhao (2)
  Xiaolu Li (2)
  Na Wang (2)
  Jijie Chai (1) (2)
  Maojun Yang (2)
  
  1. College of Biological Sciences, China Agricultural University, Beijing, 100083, China
  3. National Institute of Biological Sciences, Beijing, 102206, China
  2. MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
  
• ISSN：1674-8018

文摘

The transition metal cobalt, an essential cofactor for many enzymes in prokaryotes, is taken up by several specific transport systems. The CbiMNQO protein complex belongs to type-1 energy-coupling factor (ECF) transporters and is a widespread group of microbial cobalt transporters. CbiO is the ATPase subunit (A-component) of the cobalt transporting system in the gram-negative thermophilic bacterium Thermoanaerobacter tengcongensis. Here we report the crystal structure of a nucleotide-free CbiO at a resolution of 2.3 ?. CbiO contains an N-terminal canonical nucleotide-binding domain (NBD) and C-terminal helical domain. Structural and biochemical data show that CbiO forms a homodimer mediated by the NBD and the C-terminal domain. Interactions mainly via conserved hydrophobic amino acids between the two C-terminal domains result in formation of a four-helix bundle. Structural comparison with other ECF transporters suggests that non-conserved residues outside the T-component binding groove in the A component likely act as a specificity determinant for T components. Together, our data provide information on understanding of the structural organization and interaction of the CbiMNQO system.