Download MendeleyStructural basis for a homodimeric ATPase subunit of an ECF transporter
Chai, C.L., Yu, Y., Zhuo, W., Zhao, H., Li, X., Wang, N., Chai, J., Yang, M.(2013) Protein Cell 4: 793-801
- PubMed: 24104393 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1007/s13238-013-3915-y
- Primary Citation Related Structures:
4MKI - PubMed Abstract:
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 Å. 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.
- College of Biological Sciences, China Agricultural University, Beijing, 100083, China.
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